Yes. There is a flame detector and a solenoid that will shut off the fuel gas if the flame goes out. Another safety feature is the Level Sensor that ensures the U-Tube is filled before starting. There is a gas/air mixture that is flammable and, if the U-Tube is not filled, can escape outside causing a potential fire hazard.go to app settings and press "Manage Questions" button.

The supplied gas regulator does not go on the gas cylinder but is fixed on the back of the instrument. It will handle the pressure straight from propane, butane, or LPG cylinders (20Bar or less). The user needs to provide a hose connection at the cylinder for attachment to the provided hose. They will just use the shut-off valve on the cylinder to provide or turn off the gas.

It varies a little between 0.2 - 0.3 L/min.

No. Acetylene can not be used because it is too hot. It could melt some of the materials and the emissions will be shifted in wavelength outside of where we are measuring.

In general, Propane is better than natural gas. The lower caloric content in natural gas will not excite the ions as much so you will lose some of the low end sensitivity. Depending on the nature of your samples, that may or may not be an issue. Once an instrument is configured for natural gas it cannot be used for Propane. It would be possible to convert it back to Propane but that would require going inside the instrument and replacing a few parts. Not a very practical situation. If you absolutely must use natural gas it will probably still work for you. I encourage you to use Propane. The bottles are readily available (I use regular barbeque Propane) and if needed, you can get special Instrument Grade Propane from chemical supply houses. I only mention that depending on your samples and how low you need to measure.

That pressure is right on the threshold of what is needed. If it is closer to 1.7 kPa than 2.1 kPa there might be a problem. I recommend Propane/Butane/LPG if at all possible. Can natural gas be obtained in a bottle? If so, that would allow a higher pressure and we would be certain it will work.

Question: 99.9%, 99.5%, 99.0% are percentage purities of gas available. In the manual you suggest that butane is better for barium (Ba) readings. What about sodium (Na) readings? Do Na readings show increased accuracy in butane vs. propane? Answer: There is no increased accuracy with Sodium using either Propane or Butane. The purity of gas depends on how much precision you need, the levels you will be measuring, and the environment you are using the instrument in. Most industrial users do well with regular "BBQ" Propane. We have a customer in a similar business as you and he prefers to use instrument grade. I would try the regular Propane and see if you get good results before going to the more expensive grades. If you want to use Butane you may need to go to a higher grade from a chemical supply house.

There is no increased accuracy with Sodium using either Propane or Butane.

Yes, the BWBXP can be used with cylinders. That is how they are used at BWB and by most of our customers. The pressure of propane in such bottles is a bit less than 20 bar and butane is a bit less than that. The in-built regulator will handle that input. It delivers 37 mbar to the instrument. The pressure supplied should be somewhat above the 37 mbar to ensure a good regulation but I am not sure just how much more it should be. The flow is dependent on the flame setting and usually runs about 0.23 l/min.

Your desire to enclose the instrument in a fume hood should be OK. The amount of heat generated is not as much as hotter spectrophotometer types and that flow rate should be very adequate to remove all the heat. The calibration will be somewhat affected by ambient temperature fluctuations. The amount would be determined by just how much fluctuation there is. However, we have a unique feature we call Calibration Correction. It allows even a multiple point calibration to be easily corrected in less than a minute. This feature can be used not only across the day but over days and weeks. To get a better understanding of this feature please view the video on our website

It should be OK with a few suggestions: Keep the rate of air flow in the fume hood the same throughout the session. Keep the flow as low as possible to still perform as needed. Do calibrations and sample readings the same while the fume hood is operating

We do not use a water separator nor is one needed with our BWB Flame Photometer. Other makers use a much higher air pressure and requirethe water separator. Our compressed air is lower and does not have the issue of water falling out. A test was completed using a humidity chamber and the only way that water came out was to have a steaming bath in the chamber where the compressor was drawing up the visible steam

Question: For using Propane as a fuel supply are there any special Grade requirements? Answer: For Propane you can get a standard cylinder at many locations that supply this for common barbecue use or common heating systems which are applicable to use with the BWB Flame Photometer.

Questions: Gas requirements- what pressure and flow rate of gas is required for the BWB XP flame photometer? Can it work off gas cylinders (small 5/10kg canisters) or 'gas containers'? We do have pressurised propane gas lines within the building but if the system was installed into an area where there was no gas supply. What matrices can be analysed? Would the presence of heavy metals (such as uranium) interfere with the analysis? Have you analysed Lanthanide series elements such as gadolinium? The obvious advantage is that it is a small, compact unit, easily transported and would fit into a small space. We would install within a fume hood enclosure with an extract of 0.5 to 1m/s. Would this be sufficient to remove the heat generated from the flame? If the ambient temperature was fluctuating, would the calibration be affected? Answers: Yes, the BWB-XP can be used with cylinders. That is how they are set up by BWB Technologies and most of our customers also use them. The pressure of propane in such bottles is a bit less than 20 bar and butane is a bit less than that. The in-built regulator will handle that input. It delivers 37 mbar to the instrument. The pressure supplied should be somewhat above the 37 mbar to ensure a good regulation. The flow is dependent on the flame setting and usually runs about 0.23 l/min. The BWB-XP is a low temperature flame emission spectrometer. As such, it only measures Na, K, Li, Ca, and Ba. That is one of the main advantages for most users, if these are the only elements one is interested in. Most of the other elements do not interfere making the analysis much easier. The Lanthanides cannot be analysed. Your desire to enclose the instrument in a fume hood should be OK. The amount of heat generated is lower than most other spectrophotometer types and that flow rate your hood provides should be very adequate to remove all the heat. The calibration will be somewhat affected by ambient temperature fluctuations. The amount would be determined by just how much fluctuation there is. However, we have a unique feature we call Calibration Correction that makes even a multiple point calibration easy to correct for in a matter of less than a minute. This feature can be used not only across the day but over days and weeks. To get a better understanding of this feature please view the video on our website on www.bwb-america.com

Question: What value inlet gas pressure is recommended for the BWB XP flame photometer? Our customer has the pressure gas distribution in the range of 1.7 to 2.1 kPa. Is this a suitable pressure for the BWB Flame Photometer? Answer: That pressure is right on the threshold of what is needed. If it is closer to 1.7kPa than 2.1kPa there might be a problem. I recommend Propane/Butane/LPG if possible

If for some reason the nebuliser is accidentally changed from the factory pre-set position or the raw readings displayed are unstable or are exceptionally low, then the needle will need to be re-set. This can be achieved by following the simple steps below: Turn on the flame and wait until the machine has reached a stable temperature. Aspirate DI water. Loosen the nebuliser needle locking nut. Slowly unscrew the needle from the nebuliser until bubbles start appearing from the aspiration tube. Screw in the needle until the bubbles just cease. Aspirate 100ppm K solution. Place the machine into Read mode. Slowly screw the needle into the nebuliser, adjusting it by 1/8th of a turn at a time and adjusting the gas to provide a stable flame. During this adjustment monitor the Raw readings of K on the LCD. When the readings reach their maximum value make a final gas adjustment. The Factory minimum for 100ppm K is 26000 Raw. (A nebuliser set on one machine may differ in readings when fitted to another) Aspirate DI Water. Do a single point calibration of 100ppm K. After calibration aspirate 100ppm K and monitor the accuracy of the ppm reading. The factory maximum tolerance is +/- 1.5% over 1 minute.

Multi Mode is a special method of calibration where you can make calibration solutions that contain several ions at the same time and then can calibrate them together. The fastest way to access Multi Mode is to press the Multi Mode key. You can also turn on Multi Mode by going to Calibrations/Calibrate Ion/key 8/Multi Mode. Toggle the Accept key to turn on each ion you want to include. It is especially useful when doing multiple ions at many calibration points because it saves a lot of time.

Crect'd stand for Corrected, in this case indicating the calibration was corrected. We have a Calibration Correction function where an original calibration can be corrected for Blank and/or Max. Again. It is a time saver especially for multiple point calibrations. After you have done a calibration and the instrument has either drifted or the flame setting has changed (like when you start it up the next day) you do not need to complete a full re-calibration. Instead complete the following steps: Go to Calibrations/ Edit Calibration Choose which ion (or Multi) you want to correct. The Blank corrects the baseline. The Max is corrected by running the highest calibration concentration only and shifts the rest of the curve. You do not need to do all the other solutions. The correction can be re-corrected or erased.

Yes, all five ions can be calibrated in Multi Mode. However, Ca will interfere with Ba and should not be present when calibrating or reading Ba. With regard to correcting calibration mode/ menu, which point is available to correct? (blank or each point on multi point calibration?) Both the Blank and the curve can be corrected but they are corrected independently. When correcting a multi point calibration all the points will be corrected when correcting for the highest concentration. Run your Blank and, if it does not read zero, correct for it by choosing that option. Run your highest calibration point and, if it is not right, correct for it. Please explain the meaning of “drift”. What are the causes of drift? Drift is when conditions have changed since the last calibration or correction. Some reasons for drift are ambient temperature changes throughout the day, atmospheric pressure changes, and humidity of the air changes. Some samples can cause clogging which will show up as drift. The calibration correction function makes it easy to adjust for these without needing to do a full calibration.

Multi-point calibrations can be done with up to 10 points (plus Blank) for each ion on the XP and XP Plus. The BIO and BIO-943 up to 5 points (plus Blank).

Multi-point calibrations can be used in all cases and are recommended when greater precision is needed. Single-point calibrations should only be done when the concentrations of the samples are at or below those stated in the Operating manual (Section 6.2 - Optimum Measurement Ranges). For example, if measuring Na around 20 ppm it is OK to do a Single-point and a Multi-point could improve the results but may not need it. If the Na samples were up to 80 ppm it would be best to do the Multi-point. When doing a Multi-point and the samples are known to be close to each other try to bracket around that concentration. In our 80 ppm (with a tolerance of +/- 10 ppm) Na example, I would calibrate at 70, 75, 80, 85, and 90 ppm. That will give you very good precision within you tolerance. As many as 10 calibration points can be done with the XP, plus the Blank.

Yes, the Ion Resolution is setting the decimal point. There is a maximum of four digits total displayed with a maximum of three decimals. If the reading is from 0 to 9.999 three decimals can be displayed (if wanted) If the reading is from 10.00 to 99.99 only two decimals can be displayed (even if three is chosen) If the reading is from 100.0 to 999.9 only one decimal can be displayed Above 1000 no decimals can be displayed. It is set at one decimal at the factory and it is recommended to keep it at that setting unless you need to see more decimals as the reading will be more noisy with more decimals showing

Our photometer does not convert between the different concentration units. It only displays what the user wants to use. The display can be changed between ppm, mmol/l, meq/l, and mg/l to reflect to what units the user has calibrated. There is another option called "Units". This is for the situations where the user wants to use other than what is there. They will then need to remember what units they are using. They can change the display to Units (Main Menu, Setup, Ions, Next Calibration) and then calibrate using micro-moles/liter calibration solutions. The instrument will then give results in micro-moles/l

Once a calibration is done on an ion it remains until it is either erased by the operator, recalibrated, or adjusted using the Calibration Correction feature. Each ion is independent so these actions can be done to any or all ions. The Calibration Correction is particularly useful so a full calibration does not need to be done very often. The instrument can be corrected over days, weeks, and even months.

Yes, all flame photometers require a period to reach thermal equilibrium. The exact time will depend on the conditions of the local environment. Looking back through quite a few logs, the rate at which the XP warms up is generally between 0.4 - 0.5°C per minute. An internal study was done on the warmup procedure which gave an average warm-up rate of 0.45°C per minute (note the fan was OFF). On average if the ambient is approximately 20°C and the target is 32°C then warm-up should be achieved in 12 / 0.45 = 27 min approx. or worse case 30 min. Having said that it is recommended to leave 40 minutes for the warmup period – it was observed that the best signal stability is apparent at a little after the temperature reaches 32°C (normal control level). There is no steady correlation between warm-up rate and ambient temperature although common sense says that there should be (meaning there are other factors e.g. if the machine has already been run and left to cool down the warm-up rate will likely be higher). BWB Technologies doesn’t currently have any data on humidity vs warm-up; we did some checks on stability vs humidity some while ago and could find no clear link.

There are two reasons to not use methanol or butanol: There could be a slight attack on materials. The Butanol could swell the aspiration tubing with prolonged use and could attack the epoxy bond on the nebuliser. The flame characteristics will be changed. This could cause either an enhancement or a depression of the signal.

The Diluent Concentrate is a non-ionic surfactant that is used to lower the surface tension of the Calibration Standards and the Samples to keep the aspiration the same. The more the Calibration Standards and Samples are the same, the better the results. If the Samples are simple salt solutions, the Diluent Concentrate does not need to be done but it will improve the aspiration. If the Samples contain proteins or oils the Diluent Concentrate will help to keep the aspiration the same between the Samples and the Calibration Standards

If the instrument is fully warmed up (at least 45 minutes) and calibrated properly with a 50 ppm Standard, it should then read 50 ppm with that same Standard used as a sample. All solutions should be fully mixed and good laboratory practices are needed to achieve good results. Avoiding contamination and ensuring cleanliness are important. Remember to do calibrations and readings with the same technique. Use the same cup size and place the cups in about the same position. Do not hold either with your hands while measuring.

Questions: Will the calibration point be corrected automatically on the BWB Flame Photometer when correcting the maximum value only or both values and blank? Does this mean we cannot alter the correcting point between blank or max? Answer: When doing the Max correction all the points, except the Blank, are corrected at once. The Blank is corrected by itself. No, you cannot correct one of the points in between. The "Edit Calibration" menu is where you go to do the calibration correction. First it asks which ion you want to edit. You can choose one or more ions or, if you have a Multi calibration, you can choose to do all of them with one key stroke.

Questions: Please confirm the availability of calibration of 4 or 5 ions at one time on multimode. Regarding correcting calibration mode/ menu, which point is available to correct? (Blank or each point on multi point calibration?) With reference to question 2, please explain the meaning of “drift”. What are the causes for drift? Answers: Yes, all five ions can be calibrated in multi-Mode. However, Calcium will interfere with Barium and should not be present when calibrating or reading Barium standards or samples. Both the Blank and the curve can be corrected. Run your blank and if it does not read zero correctly for it by choosing that option, run your highest calibration point. When correcting a multi-point calibration all the points will be corrected when correcting for the highest concentration. Drift is when conditions have changed since the last calibration or correction and the instrument will not still be calibrated. Some reasons for drift are ambient temperature changes throughout the day, atmospheric pressure changes, and humidity of the air changes. The calibration

Answer: Yes, the calibration standards are provided with Certificates of Analysis and Material Safety Data Sheets.

Questions: We routinely perform 6-point calibrations for both Sodium and Potassium and I notice that the software does not display calibration graphs for the parameters of interest? Answer: We do all the ions as a linear function, meaning that the more calibration points there are surrounding the expected concentration the higher the accuracy. We state the higher concentrations are achievable, but I do not recommend doing that. It is always better to dilute the samples to around 100ppm or lower (or the equivalent with the other units). There are two reasons for this both of which make it easier on the user. 1. Higher than 100ppm and the interferences between ions starts to become significant. This will throw off the results or will require matrix corrections when calibrating. 2. High concentrations of salts will build up in the mixing chamber/burner where they can come off sporadically causing an unstable signal. This then requires those parts to be cleaned very often, possibly several times a day, which is not very desirable for the user.

Answer: BWB Technologies recommends the BWB Flame Photometer user to follow the Quick Start Guide through step 10. Mix at least one set of Calibration solutions using the materials in the Starter Pack. We recommend making two Potassium (K) solutions at 100 mg/l (1 ml of Standard Concentrate brought to 100 ml) and 10 mg/l (10 ml of 100 mg/l brought to 100 ml). A Blank solution (Deionised water) should also be available. Please plan on having the BWB-XP warmed up for at least 45 minutes before measurements are conducted.

Answer: There is an option called Ion Resolution which allows for the editing of the decimal points displayed. There is a maximum of four digits total displayed with a maximum of three decimals. That is, if the reading is from 0 to 9.999 three decimals can be displayed (if wanted), if the reading is from 10.00 to 99.99 only two decimals can be displayed (even if three is chosen), if the reading is from 100.0 to 999.9 only one decimal can be displayed. Above 1000 no decimals can be displayed. It is set at one decimal at the factory and BWB Technologies recommends keeping it at that setting unless the user requires for decimal places as the reading will become noisier with more decimals showing.

Question: Is it possible to convert the results displayed in ppm to µmol/l? Can your flame photometer convert ppm in µmol/l? Answer: The BWB Technologies flame photometer does not convert between the different concentration units, it just displays what the user wants to use. The display can be changed between ppm, mmol/l, meq/l, and mg/l to reflect what units the user has calibrated to. There is another option called "Units". This is for situations like this where the user wants to use other than what is there. They will then need to remember what units they are using. They can change the display to Units (Main Menu, Setup, Ions, Next Calibration) and then calibrate using µmol/l calibration standards. The instrument will then give results in µmol/l however it will not have µmol/l written on the output.

Question: Is it possible to save the calibration values on my BWB XP flame photometer? Is there the possibility to save the calibration values? Answer: Once a calibration is done on an ion it remains until it is either erased by the operator, recalibrated, or adjusted using the Calibration Correction feature. Each ion is independent so these actions can be done to any or all ions. The Calibration Correction is particularly useful so a full calibration does not need to be very often. The instrument can be corrected over days, weeks, and even months. Re-Calibrating the instrument is dependent on environmental interferences, such as ambient humidity and temperatures.

Answer: The Diluent Concentrate does not need to be used with all samples. It is a non-ionic surfactant that is used to adjust the surface tension. You may see a slight increase in signal because the drops in the mist will be smaller so more make it to the flame. Its real use is when samples have materials that affect the surface tension, like alcohols, proteins, oils, or fats. Using the Diluent Concentrate in the samples and standards will help to make the surface tension the same with both to give better results. If the samples are simple salt solutions it is not needed at all. It is very important to use good DI water and I see that you are doing so with an exchange resin bed.

Answer: I think you are asking how many calibrations you can get out of the 150ml bottles of 10,000mg/l we provide. When diluted to the proper level (close to or under 100ppm) there is enough to do 4,600 Na calibrations and 76,000 K calibrations, assuming 10 ml per calibration. Even with many calibrations per day that is more than enough for the two years expiration of the standards. These diluted standards should be made fresh daily.

These appear to be blood serum samples. Yes, they can be detected easily by the BWB-XP. However, they will need to be diluted. Most users dilute by 100:1. Therefore, the standards will need to be made to the diluted values to calibrate. Before calibrating the BWB-XP set the units to mmol/l under Setup/Ions/Next Calibration. There are two options that can be done with the calibration at this point. Use the diluted values (1.40 mmol/l, 0.051mmol/l) and it should be noted to multiply the result by 100 to get the results and account for the 1:100 dilution of the sample. Alternatively, it is possible to set the instrument that the diluted standards are the concentrations before diluting. Then, they can read the results directly. The first option will be more precise. The second option is easier and will probably give results within the tolerance they want.

We do not have "Percent" as a display option for units. We do provide a "Unit’s" option so a user can have whatever they want. The instrument will need to be calibrated with standards made in the units desired. The instrument will not calculate from one unit to another. It is important when talking about maximum concentrations to distinguish between the raw sample and what is best for the instrument and getting good results. The raw sample can be very high but, through dilution, it can be brought down to practicable levels. Although concentrations of 1000ppm (or equivalent) can be run through the BWB-XP there are some issues that make doing so impractical. 1. If the sample only has one ion it is not so bad. When more than one ion is present, they will probably interfere with each other at this high a concentration. Even ions that the BWB- XP does not measure can interfere. 2. Higher concentrations will cause salt to build up in the Mixing Chamber and Burner parts. This salt will eventually cause wild readings as it comes off and enters the flame. Those parts will then need to be cleaned. The frequency of cleaning will depend on the concentration and number of samples. Dozens of samples every day at 10ppm may not need cleaning for a month but a dozen samples run in one day at 1000ppm may need cleaning every day. BWB Technologies highly recommend that samples be diluted to 100ppm or less. This is the approximate level where interferences start to become significant, and the salt build up is not too much of a problem.

We do not use a water separator, nor do we need one with our BWB-XP flame photometer. Other makers use a much higher air pressure and do need the water separator. Our compressed air is lower and does not have the issue of water falling out. I did a test using a humidity chamber and the only way that water came out was to have a steaming bath in the chamber where the compressor was drawing up the visible steam.

Question: We sometimes receive inquiries that end user in pharmaceutical field who uses automatic flame photometer made by Instrumentation Laboratory (IL) in Italy is considering to replace flame photometer with new one. The one specific feature of IL flame photometer is measurement of particle sample (e.g. the minimum is 20 μl). Then could you please advise us 1. how much amount of sample is the minimum for BWB-XP? 2. the idea to measure small amount sample. Answer: We are familiar with the Instrumentation Laboratory instrument. The pharmaceutical use of the IL is for measuring blood plasma and urine. These samples need to be diluted by 100 to 1. Therefore, a 20 µL sample then becomes 2000 µL or 2 mL. We aspirate at about 3 mL per minute. Most readings stabilize within about 15 to 20 seconds so 2 mL can be measured using the BWB.I suppose that there are other pharmaceutical users that want to measure other than plasma and urine. Almost all the time the sample will need to be diluted. How much will depend on the actual sample. Even for industrial users with valuable samples will probably need to dilute also. Always keep in mind that flame photometry works best at lower concentrations. There is less self-absorbance and interferences are minimized.

Question: Could you please explain to me why it is good to use Diluent Concentrate, how does it react? Answer: The Diluent Concentrate is a non-ionic surfactant that is used to lower the surface tension of the Calibration Standards and the Samples to keep the aspiration the same. The more the Calibration Standards and Samples are the same the better the results. If the Samples are simple salt solutions the Diluent Concentrate does not need to be used although it will improve the aspiration. If the Samples contain proteins or oils the Diluent Concentrate will help to keep the aspiration the same between the Samples and the Calibration Standards.

First, it depends on the nature of the sample. If the concentrations are more than about 100ppm they would want to dilute before aspirating. Higher concentrations of salts will form deposits inside the mixing chamber and burner. They would need to be cleaned often which would cause them to take the instrument off-line. That could be as often as every hour at 1000ppm. Another issue is the environment where they would situate the instrument. Process facilities are generally dirtier than laboratories. Any dust or smoke in the air will be drawn in and cause instability of the readings. Temperature is also an issue. Will the ambient temperature change during calibrations and readings? If so, that could further muddle up the situation. The instrument will need to be situated close to the pipe. The aspiration tubing needs to be kept as short as possible. The longer it is the less sample is aspirated until nothing will be drawn up. There is an active flame and some process facilities can have explosive materials that they do not want anything flaming anywhere near the process (in case it escapes). As you see there are some aspects that make it difficult to say if a particular user can do other than what the instrument was designed for. They would need to be responsible to integrate the instrument into their process and solve these issues.

Question: We have a customer who asks about the minimum sample volume to introduce in the instrument for good measurements; could you please help me? This customer is using between 100-200 µl. The concentration of the samples is around: Sodium Na: 140meq/l Potassium K: 5meq/l Lithium Li: 0.6meq/l Answer: Our flame photometer uses about 1-2 ml of final sample to get a reading. That is 10x what your customer is doing now. However, their concentrations of Na and K will need to be diluted for best results. The Na should be diluted by 1:100 or 1:200 ratios. The K can be diluted by 1:10. The Li will be fine without dilution. This is due to low concentrations reducing interferences as well as self-absorbance.

Question: Please let us know the following about the following specifications of the BWB Flame photometer. Range: ? (Is it 0 to 199.9 ppm?) Sensitivity: Na: -3 to 100 ppm K: -3 to 100 ppm Li: - 5 to 100 ppm Ba: 100 to 200 ppm Reproducibility: Unknown Answer: Our range for all elements is 0 to 1999ppm. Sensitivity is not usually expressed as a range. We quote ours as "limit of detection" (see specification on web site) Similarly with reproducibility - this is embodied in the limit of detection specification. To meet the LoD spec the reproducibility must be no more than twice that spec.

Questions: What does Multi mode mean and how do you switch this option on? I made calibration for sodium Na, Potassium K, Calcium Ca. When I switch to View Calibration there is written for K (on the raw, where raw data is shown) Crect, what does it mean? In the software: Calibrate Tab, clicking the calibration box for K, there is written for resolution: +/-8.1e - 005ppm, for Na there is simple +/- 0.00015ppm, what does 8.1e mean? Answers: 1. multi-Mode is a special method of calibration where you can make calibration solutions that contain several ions at the same time and then can calibrate them together. The easiest way to show you is to go to our website, www.bwb-america.com, and watch the video section on Multi Mode. The fastest way to access it is to press the Multi- Mode key. Or go to Calibrations, Calibrate Ion, key 8, multi-mode. When there toggle the Accept key to turn on each ion you want to include. It is especially useful when doing multiple ions at many calibration points because it saves a lot of time. 2. Crect'd means that that calibration was corrected. We have a Calibration Correction function where an original calibration can be corrected for Blank and/or Max. Again, it is a time saver especially for multiple point calibrations. After you have done a calibration and either the instrument has drifted, or the flame setting is changed (like when you start it up the next day) there is no need to do a complete re-calibration. Go to Calibrations, Edit Calibration, and choose which ion (or Multi) you want to correct. The Blank corrects the baseline. The Max is corrected by running the highest calibration concentration only and shifts the rest of the curve. No need to do all the other solutions. Again, the web site video shows it in operation. The correction can be re-corrected or erased. 3. It is a floating decimal format. It switches from the "normal" form (like the 0.00015 you are seeing for Na) to the exponent form when the exponent is less than -4. In your case it is equivalent to +/- 0.000081ppm (8.1 exponent minus 5)

Question: I am interested in your photometer however it is vital that it can convert the results displayed from ppm to µmol/L. Can the BWB flame photometer convert ppm to µmol/L Answer: Our photometer does not convert between the different concentration units. It just displays what the user wants to use. The display can be changed between ppm, mmol/l, meq/l, and mg/l to reflect what units the user has calibrated to. There is another option called "Units". This is for situations like this where the user wants to use other than what is there. They will then need to remember what units they are using. They can change the display to Units (Main Menu, Setup, Ions, Next Calibration) and then calibrate using micro-moles/litre calibration solutions. The instrument will then give results in micro-moles.

Question: How to choose between using one point and multi-point calibration with a BWB XP flame photometer? Answer: Multi-point calibrations can be used in all cases and is recommended where greater precision is needed. Single-point calibrations should only be done when the concentrations of the samples are at or below those stated in the Operating manual (Section 6.2 - Optimum Measurement Ranges). For example, if measuring Na around 20 ppm it is OK to do a Single-point and a multi-point could improve the results but may not need it. If the Na samples were up to 80 ppm it would be best to do a multi-point calibration. When doing a multi-point and the samples are known to be close to each other, try to bracket around that concentration. In our 80 ppm (with a tolerance of +/- 10 ppm) Na example, I would calibrate at 70, 75, 80, 85, and 90 ppm. That will give you very good precision within your tolerance. As many as 14 calibration points can be done, plus the Blank. Question: Providing Fuel: “The source should be regulated to no more than 20Bar with a flow rate at least 0.4l/min”, would you please inform at what pressure does the instrument achieve the optimum result? (We try to use> 0.16Mpa, the result is OK.) Answer: When propane is pressurised into a bottle the resultant pressure is a bit below 20 ar. Butane is quite a bit below propane and LPG is somewhere between. The attached gas regulator is sized to give the optimum result with them all and no further regulation is needed if your gas comes out of a bottle. The operating pressure of the regulator is 37 millibar and your 0.16 MPa is about 260 mbar, which is sufficient. Question: If we prepare the standard solution strictly following the operation process with a value of 50ppm, does the value show on the screen have any possibility not to show 50ppm? (Maybe the value is higher or lower. Should we mix the standard solution well in advance or there are some other reasons?) Answer: If the instrument is fully warm (at least 45 minutes) and calibrated properly with a 50 ppm Standard, it should then read 50 ppm with that same Standard. All solutions should be fully mixed and good laboratory practices are needed to achieve good results. Avoiding contamination and ensuring cleanliness are important. Remember to do calibrations and readings with the same technique. Use the same cup size and place the cups in about the same position. Do not hold either with your hands while measuring. Question: In order to ensure sampling precisely, can we use a transfer pipette? Answer: Yes. Whatever method and equipment used the result will depend on the tolerance of the equipment and technique. Be aware of contamination and try to minimise this. Question: Time to Stability: Less than 15 seconds after sample is introduced to the flame. Why does the value continue to change when the sample introduced to the flame within 15 seconds? Answer: Introduced to the flame is not the same as starting aspiration. Depending on the nature of the sample it can take 3-5 seconds to go up the aspiration tube, into the nebuliser and through the mixing chamber before it reaches the flame. Be sure the instrument is fully warmed. Question: What is “De-proteinising solution” and “Decon 90”? Would you please explain in detail? Answer: De-proteinising solution is any cleaning agent that works well cleaning off proteins. Decon 90 is one of these types of cleaning agents that we provide. Proteins in samples can clog the capillary tube on the nebuliser and, with extended use, form a coating in the mixing chamber and burner tube where they can affect the results. Question: PC Software: Does the save path of the report be changed? (Don’t save in disk C) Answer: The software needs to originally save it where it does. After it saves it there you can go get it (click on "Reports" button) and transfer it to wherever you want, another file, to disc, or as an attachment to an email. You can even print it out! Question: Does the Flame Photometer need to be put in a Fume Hood? Answer: We have not tested the instrument in a Fume Hood. I see no reason why not, but I should think it will be OK with a few suggestions. Keep the rate of air flow in the fume hood the same throughout the session. Keep the flow as low as possible to still perform as needed. Do calibrations and sample readings the same while the fume hood is operating.

Answer: We supply 10,000 mg/l calibration solutions that can be made into these. For all these solutions the ions in question are all single valence so mEq/l is the same as mmol/l. To convert mmol/l to mg/l multiply by the atomic mass. For example, the Li=15mmol/l (same as 15mEq/l) is multiplied by 6.94g/mole giving 104.1 mg/l. To make this from our solutions it is easiest to use the equation V1xC1=V2xC2. If you want 500 ml of 104.1 mg/l that would be 0.500 litre x 104.1 mg/l = X x 10,000 mg/l. Solve for X = 0.0052 litre. So, take 5.2 ml of the 10,000 mg/l solution and dilute to 500 ml. Use the part numbers: 1. 019-010, Na Cal. Standard 10,000 mg/l. 2. 019-011, K Cal. Standard 10,000 mg/l. 3. 019-012, Li Cal. Standard 10,000 mg/l. 4. 019-015, Diluent Concentrate. 5. 019-050, Decon 90 Concentrate

In general, Propane is better than natural gas. The lower energy content in natural gas will not excite the ions as much so you will lose some of the low-end sensitivity; depending on the nature of your samples that may or may not be an issue. Once an instrument is configured for natural gas it cannot be used for Propane. It would be possible to convert it back to Propane but that would require going inside the instrument and replacing a few parts which is not a very practical situation. If you absolutely must use natural gas, it will probably still work for you. I encourage you to use Propane. The bottles are readily available (I use regular BBQ Propane) and, if needed, you can get special Instrument Grade Propane from chemical supply houses. I only mention that depending on your samples and how low concentration you need to measure.

Question: The client often measures high concentrations of Sodium (Na) and Potassium (K). Generally, they are measuring the diluted sample with DI water. The problem is after calibrated using standard solutions 500ppm and 1000ppm for Na and K on multi-mode, measuring the standard solution again to confirm the accuracy, normally it will display a little bit high, about 5% higher than standard solution. And next day, measuring the same standard solution again, at this time, it will display too low, in case of 500ppm, it shows about 400-420ppm. Despite using the same standard solution, what is the reason the results change during that time? Do we calibrate the instrument every day before measuring the sample? Answer: First, I think your customer needs to dilute even further. I suggest they dilute to 50-100ppm or further down. They should get better results because the Na and K will not interfere with each other so much and it will limit salt build up in the Mixing Chamber and Burner that can cause instability. There are many things that affect the calibration. It can change hourly or throughout the day. The next day it can be off by quite a lot. Recalibration is needed often but we have added a feature to make this situation easy for the user. We call it Calibration Correction. It can be used on both a single point and multi-point calibration. I will give you an example of how it works. I start by doing a multi-point calibration at Blank, 25, 50, 75, and 100ppm. At a time later I want to check the calibration, so I run the 100ppm standard (the highest concentration standard) and it reads 90ppm. I then can use the Calibration Correction function. While running the 100ppm standard I tell the instrument to correct back to 100ppm. When I do the calibration correction the whole calibration curve inside the instrument is adjusted and there is no need to run all the standards. Here is how to use the Calibration Correction. 1. It can only be used when there is a calibration for that ion. 2. Go to the Calibrations Menu or key the Calibration button. 3. Go to Edit Calibration. 4. Choose which ion you want to edit. Key the number of the ion on the display. There is an option to do Multi correction. 5. You will now see a menu where you can Delete, Correct for Maximum, or Correct for Blank. To correct for Maximum run the highest concentration standard used in the original calibration and key accept. To correct for Blank use the original Blank solution. You have now corrected the calibration. The calibration can be re-corrected many times and the correction can be deleted without deleting the original calibration. With a bit of practice through the menus it becomes very easy to correct the calibration so it can be done as often as needed. You can see how to do this on the video on our web site. You may be happy to learn that we have a program to translate the video into many languages. In addition to English, we now have German and Mandarin Chinese, French, Spanish and Russian. See www.bwb-america.com

Question: Our sample has very high concentration of sodium (Na) and Potassium (K) and is a solid. Normally we dissolve it in deionised water (DI) (the sample: 0.1g, DI water 100ml). Sodium is 400ppm and for potassium, it is 970ppm. For this reason, we use this high concentration as our standard. What are your suggestions to get optimum results from your flame photometer? Answer: I would dilute further down. Dissolve the 0.1g sample in 1000ml DI water or 0.01g in 100ml. That will then be around 40ppm Na and 97ppm K. Then do a Multi-Point/Multi Ion Calibration, again you can see how in our video on our website. I will give you an example using three calibration points (plus the Blank) for each of these ions. They can do more points if wanted (up to 14 points for each ion). 1. Make up three calibration solutions with both Na and K present. Solution 1 will be 30ppm Na and 90ppm K. Solution 2 will be 40ppm Na and 100ppm K. Solution 3 will be 50pm Na and 110ppm K. 2. Start the flame and fully warm up (45 minutes is the recommended warm up time). 3. Press key 2, Calibrations. 4. Press key 1, Calibrate ion(s). 5. Press key 8, Multi. 6. Press key 1 for Na and 2 for K so they display "Yes" When both displays yes, press key 8, ready. From here on follow the prompts. The Back key will go back to the previous item if you make mistakes. 7. It will now ask you for how many points are desired. For our example we put in 3 and key Accept. 8. Then it asks to aspirate Blank and key Blank. 9. Next it will ask for the concentrations in Solution 1. Key 30 for Na (Accept) and 90 for K (Accept). Aspirate Solution 1 and key Accept. 10. Repeat for Solution 2 (key 40 for Na and 100 for K) and Solution 3 (50 for Na and 110 for K). The instrument is now calibrated for both Na and K at those concentrations. To do the Calibration Correction for Maximum, as I discussed before, use Solution 3. Both ions will then be corrected for.

Questions: I have noticed that even after 30 to 40 minutes the sodium and potassium raw readings are not really stabilising, and the indicator shows a small "Blob" with the raw readings shifting by no more than one unit for each of the ions. So for example 63 will flick to 64 then back to 63. I guess that the instability of the readings could be caused by some factors? What are some of the main types of environmental interferences that can influence reading stability? Answers: Everything you mention about the environmental situation will affect the stability. Na will be the worst because there is a lot of Na in smoke, dust, exhaust and hair. The K is not quite as prevalent in the environment as Na and Li is not at all. You don't really need to weigh small amounts of your sample to be accurate. Weigh what you can and dissolve in a large volume then dilute down (which you want to do anyway). For example, if your scale can weigh to 0.1g weighing 10g will put you +/- 1%. Weighing 100g will be +/- 0.1%. The “Blob” in question is a qualitative representation of the noise present when a measurement is taken.

Gas Supply Check the gas supply is turned on at source and it is not exhausted. Ensure the gas source is properly regulated to no more than 20bar. Test hoses and connections for leakage and repair as needed. Air supply Check the correct position is selected on the rear panel switch for the air supply being used (Internal or External). From the Start Up menu, select the Maintenance menu and Run Compressor. Check the compressor is running. Remove the tubing from the air inlet and ensure air is flowing out of the tube. If not consult your local agent or BWB regarding compressor service. U-Tube Check the centre of the drain cup is filled with water and that the check U-tube LED is not lit. If the drain cup is filled with water but check U-tube LED is lit, check the Level Sensor is plugged in and the float has not stuck. Spark During Start Up visually check, through the Inspection Port, that a spark is generated to the centre of the flame spreader, indicating the ignition system is working. If no spark is seen, unplug the power cord, remove the Outer Chimney Rear Plate and check that the lead connection to the Spark Igniter is properly attached. Fuel Gas Pre-set Perform the fuel gas pre-set adjustment. In addition to the above see HERE for flow chart

"Instrument fails to stabilise after Start Up": Check the instrument is located in a draft free location. Ensure the ambient air is clean and free of airborne particles. Check the mains supply conforms to proper standards. Check the gas supply is not fluctuating or almost exhausted and all hoses and connections are not leaking. Repair/replace as required. Check the nebuliser performance. If unsatisfactory, clean nebuliser as instructed or replace. If using an External air supply, check this is not fluctuating. Check that the there is free drain from the U-tube overflow with Tee piece fitted - no U sections where water may be trapped. See HERE for stability testing instructions

The air pump duty can go up to 255 in theory (from 165 default) but in practice it makes very little difference above 200. It can be changed at Setup->Config->Extras->Compressor.

The software needs to originally save it where it does. After it saves it there, you can go get it (click on "Reports" button) and transfer it to where ever you want. Another file, to disc, or as an attachment to an email. You can even print it out!

Stability testing instruction HERE shows how to generate an IonLog file. It is also very useful to see a report of AutoRead results. Using FP-PC S/W go to the AFHS tab. In the the lower part of the window is AutoRead Stored Results section. Click on Retrieve AutoRead Results whilst connected to the FP and all of the results stored in the FP will be uploaded. The results may be reviewed by clicking Review and also saved as a CSV file in the Data Folder (default c:\BWB Flame Photometer) by clicking Report(CSV). The filename of the file saved will depend on the current file settings. These may be reviewed / changed by selecting the Report Tab and clicking Format(Single/Multi). If Job / Batch has been selected then the filename will include the text in the Tray Reference field in the AFHS tab. If there is already a file with the name selected then a sequential number will be appended to the filename.

The phosphate ion is an extreme contaminant to Ca analysis. There could be some present from the P2O5, either as a contaminant or through unknown reactions. It does not take much to interfere. Is there any way to know if it is present? Another thing I see is the pH is very low. You might try to raise the pH but not enough to precipitate out the Calcium Hydroxide. Try Ammonia solution to not add other ions. Let me know if this helps.

I was hoping it would at least show an improvement. It is going to require some research to figure this out. The only way I can think of is to make samples that omit each component and test to see which one is supplying the interfering species. These should go through the normal manufacturing processes. Include any "inert" ingredients, like binders or flow agents, which might be present.

Good to hear that you have good results now. Yes, it is OK to add to the calibration standard, within reason. What you have done we call a matrix correction. By adding the species that is causing the interference it "reacts" the same way as in the sample. Now, when doing the calibration, you tell the instrument that you are calibrating at 100ppm but there is a fraction that is not available for measurement because of the interferent, so it is seeing less than the 100ppm. The instrument takes the lower signal and calls it 100ppm. When the sample is run it too has the same fraction that is not available so it will have the same lowering of the signal and the instrument reports the results that are now corrected for the interferent. For the best results the interfering species should be close to the same concentration as in the sample. There is a slight interference on Ca from Na, depending on the concentration. You might want to correct for that by adding the appropriate amount of Na to the Ca Standard.

These items certainly can be analyzed with flame photometry. In fact they were some of the first materials analyzed when it was invented over 70 years ago. These samples will need some form of preparation (dilution, de-proteinizing, etc.) prior to running through the instrument. Our literature is rife with various methods of preparation and we have some of them in our Guide to Flame Photometry. You need to determine which preparations are needed for your samples.

There are some things to ensure precision results: Clean the Mixing Chamber and Burner parts often. Keep the samples diluted to 100ppm or less. Do a multi-point calibration bracketing the expected concentration of the sample. Use the same techniques to calibrate and measure samples. Use the same size sample cups filled to the same level and place them in the same spot on the spill tray. Do not hold by hand.

Question and application specifics: The fluid is a brine wastewater from natural sources (deep underground). There are two different streams with main components shown below. Stream #1 - typical levels of barium are 5,000-15,000 mg/l. There is also the following but range can vary beyond numbers below: Ca: 5,000-40,000 mg/l, Na: 10,000-60,000 mg/l, Sr: 1,000-8,000 mg/l, Cl: 20,000-200,000 mg/l, and others typically in a brine water - carbonates, potassium, iron. May also have low levels of organics Will have high TDS, can be up to 300,000 mg/L. Stream #2 - Similar to above but Barium typically 1 - 200 mg/l. Answer These brine samples are a bit of a problem. They cannot be run directily through the flame photometer. The salt content is too high and salt deposits will form in the Mixing Chamber and Burner in a matter of minutes. Once they are there, they will throw off particles that will create a very noisy signal. Another reason is the interferences are huge and make it very difficult to compensate. Normally, higher salt concentrations are diluted down to relieve those situations. However, with these, to get the salts down enough, the Ba will be diluted too far to get a reading. Are you only interested in Ba and not the other ions? I think the only way to approach this is to precipitate the Ba (as the sulphate) away from the rest of the salts and redissolve (with ammonia EDTA) and then analyze. The Barium Sulphate is 1000 times less soluble than the Strontium Sulphate and 100,000 times less than Calcium Sulphate so they should not be too much of a problem as long as there is not much of an excess sulphate added. This plan will help with Stream #2. The Ba in it is very low but can be magnified through the precipitation/re-dissolution process. For example, if it is 100mg/l in the sample and you precipitate from one liter you will get 100mg of Ba. Re-dissolve into 250ml will give you 100mg/250ml or 400mg/l, four times as concentrated. Remember to back calculate for the original sample concentration. If you want to measure the other ions remaining after precipitating the Ba the sample can be diluted now and measured directly. I would recommend a 1,000:1 dilution factor.

I want to determine the level of lithium in blood serum using flame photometry, please advise whether you have calibrants in units for biochemistry (mmoles/l, etc) with the BWB XP flame photometer? Our XP standards are 10,000ppm. We have mmol/l standards for the BWB BIO and BIO-943flame photometers.

To convert into mmol/l divide ppm by the atomic mass of the ion in question (6.94 for Li). When diluting the Standard Concentrates in ppm to mmol/l be sure to do so at 20 Degrees C

It depends on what stage of production you want to measure. The actual biodiesel cannot be run through the instrument. It will attack several of the components and will change the flame temperature. It is usually the waste portion that is measured to make sure the Na and K compounds are fully washed out. Many of these are soap-like compounds and are washed out with water. As long as it is toward the last of the wash so there is not much "soap" it should be OK. The first of the wash would have too much "soap" and would foam inside the Mixing Chamber causing erratic readings.

Question I am most interested in sodium ion quantization in semi-solid or solid samples such as cheese. Secondarily I am interested in potassium. The concentration is relatively high in the solid, 1000’s of ppm, but in solution that will obviously be dependent on sample preparation. Sample preparation is key to our interest in flame photometry. While I understand that the measurement itself is straightforward, what sort of sample preparation would you expect for these samples? Is it similar to ICP? Is acid digest required? Answer The most common method for these types of samples is to ash the sample and then dissolve the ash with an acid such as nitric acid. The resulting solution should be diluted to keep the Na and K below 100 ppm. Also, be sure to filter any particulates that are usually present with ashing/dissolving methods. You will need to find a filter system that will not contaminate with Na and K. Regardless of the sample preparation, once you have the sample flame photometry has advantages over other instrumentation, as long as you are only interested in the few elements it measures. 1. If the sample is properly diluted, the interferences from other elements literally go away. 2. It is easier to use than other instruments. No adjustments of fuel and oxygenate gases, no slit adjustments nor wavelength choices. The operator need not be a highly educated (paid) spectroscopist. 3. Flame Photometers are much more affordable to purchase and fast to get final results. This translates into a more effective cost/sample ratio.

Queston: I am considering making new standards for the photometer to analyse our finished product. Typically, we measure the NaCl and other constituents such as MgCl 2 and insoluble precipitates and through the elimination of them, determine the 95-99% pure KCl we have produced. When building these standards in the past we have made up varying solutions standards of NaCl and allowing for the matrix of the others and have actually used about a 4000 ppm combined salt (NaCl, KCl & MgCl) solution. Do you think this is too high? I'd started to examine the possibility of reducing our standards down to 1000 ppm TDS. It was my understanding that even though the NaCl content was below 1000 ppm on our present standards the excess KCL/MgCl 2 added for matrix effects may be influencing the true reading of the Na. Would this be advisable? Answer: As a practical matter I think you should reduce the Standards and samples even further closer to a range of 100-400 ppm. Even lower would be better, such as a range between 10-40 ppm. This is suggested for two reasons. 1. The more dilute the samples are the less the influence of the matrix of the sample interferes with the result. 2. At such high concentrations the salts tend to crust on the inside surfaces of the Mixing Chamber and Burner parts. They then start coming off and entering the flame causing the reduction of reading stability. These parts will need to be cleaned almost hourly to increase the stability back to regular values.

That level of sulphuric acid will be OK to use

Even at low concentrations HF acid should not be used. It will attack the stainless steel capillary on the Nebuliser and Burner, the silicone U-Tube/Waste tubing, the Level Sensor, and the glass Drain Cup. It might take some time to cause a failure of these components at low concentrations but it will happen eventually. The use of HF will void the warranty

This application has some difficult issues. First is the wide range they are looking at. It is not practical to run samples that are high in salt concentrations. More than a few hundred ppm and the salts deposit on the insides of the mixing chamber and burner. They will then come off erratically and the readings will be very unstable. Therefore, the mixing chamber and burner will need cleaning often. Keep the concentrations at 100ppm or below. The lower levels will be good but the higher levels will be a problem. Do not even think about running 20000ppm! If they know their samples are low they may not need to dilute them and if they know they are high they can dilute them accordingly. If they have no idea what the concentration is before they start it will be much more difficult. The next issue is that almost everything in this system will interfere with each other at higher concentrations. Another reason to dilute the samples. Lithium- Iron at dilute levels (30ppm) starts to depress the Li response. Barium also has an effect on Li but is not too bad under 300ppm. The acids will also have an effect. Keep hydrochloric under 0.03 M and the sulphuric under 0.1M (when the samples are diluted). Barium- Iron has a very strong effect and should be absent. I am not sure about the effect of Li. The sulphuric acid will depress the response but I do not know how much. The hydrochloric is good up to 0.1 M. Since they are measuring in iron oxide the iron will be too high even if they dilute. To get the iron down to where it will not interfere, the Ba and Li will be too low. Therefore, they will probably need to precipitate out the iron. It is possible that they are already doing this and it will not be a problem. An alternative is to remove the Ba (as a precipitate) and Li (using ion exchange resins) from the samples, re-dissolve and then measure them separately. This will keep them all apart and they will not interfere so the matrix compensation will not need to be done. The interferences between the Ba and Li can be dealt with through matrix compensation techniques. That is, when making up calibration standards for each ion the other ion needs to be at the same concentration expected in the sample. For example, if the Ba is 100ppm and the Li is 20ppm all the Ba standards will have 20ppm Li and all the Li standards will have 100ppm Ba. If the acids are a bit high they can similarly be compensated.

The sample will need to be diluted. At 25% NaOH that is 250g/l or 144g/l of Na. Doing a 1000:1 dilution (1ml diluted to 1 liter) gives 144mg/l Na. This would be the minimum dilution needed. It would be better to dilute an additional 10 times (10,000:1 or 0.1ml diluted to 1 liter) to give 14.4mg/l. That will put them in the range where the Na is very well behaved with little interferences. There could be a problem with the polymer portion. If it does not precipitate out when diluting it could clog the nebuliser or coat the mixing chamber. Both would then need to be cleaned often

Ba poses issues. There cannot be any Ca present when measuring Ba. The other ions will interfere with each other at concentrations above 100ppm. The samples will need to be diluted to avoid these interferences.

The measurement of Ca can be difficult in many types of samples and fertilizer is one of them. The problem is that all of the anions will interfere with the measurement and the Ca needs to be separated from them. This will entail quite a bit of chemical techniques. There are two main types of separations to get the Ca out. If the sample is a solid the use of a Lithium Acetate solution to extract the Ca out has been successful. For liquid samples the Ca is precipitated as the oxalate and re-dissolved with perchloric acid. In our "A Guide to Flame Photometer Analysis", there are a few examples of how to measure Ca. Although those methods are not specific for fertilizers, you can try them anyway. The techniques and chemicals would be the same.

Can the BWB-XP measure urine samples up to 200 mmol/l? Is there something known about the linearity of sodium urine in the range 10 - 200 mmol/l? In your biochemical applications you describe only the measurement in serum (120-160 mmol/l). Do you have a manual for urine? Although urine is not the same as serum it can be thought of as the same when using the flame photometer. It is actually easier because it does not have all the proteins and blood cells found in serum. It does need to be diluted by at least 100:1. The response of Na at the high levels in urine will not be linear. This is one reason to dilute, to get it in the range where the Na is much more linear. Another reason is to limit the interference with other ions, particularly K. Tie that with our multiple calibration points feature and you should get very good results. There is not a specific manual for urine.

To convert use the following formulas: ppm = A x mmol/l mmol/l = ppm/A A = atomic mass of the ion. Na = 22.99g/mol, K = 39.10g/mol Therefore, 160mmol/l Na = 3,678.4ppm and 5mmol/l K = 195. 5ppm.These are "normal" for bio systems. Generally, these would be diluted by 200:1 so the Na is about 0.8mmol/l (18ppm) and the K is around 0.025mmol/l (1ppm).

Looking at these methods I would say that they would work with our instrument. I see no serious problems measuring Na. With either method the Na will be re-dissolved and can be measured in the normal manner. It will not be affected very much by the other ions at their expected concentrations. For Ca, the proteins would be burned off with the ashing method. I am not sure that the phosphates will be gone with ashing. If not, I have a reference to use EDTA to chelate the Ca to "protect" it from the phosphate. I have not tried this yet to know if it works. I do see a slight problem. If the levels of the other ions are present in the listed table (page 4 of the digestion procedure 3.0-E) the Cu, Fe, Mn, and Zn will lower the Ca results. You might be able to compensate by adding these elements to the Calibration Standards (and Blank) if you know they are present in the sample. If they are in the calibration solutions but not in the sample, then the Ca reading will be high. How will they know if they are present? If they are using another method to determine them, it should be done first to see if they are present and then they can compensate. They will need to do some investigating to see how well it will work. The only other issue is the digestion process uses nitric and hydrochloric acid mixture. I know that most of the acid will be used up in the digestion but if not, it could attack the stainless steel needle in our nebuliser which is something to be aware of.

Yes, the BWB-XP is ideally suited to be used with waters from lakes, streams, rivers, and lagoons. Depending on the concentrations of the ions the samples will probably need to be diluted for the measurement and the reading then multiplied by the dilution factor to get the result. The ranges for each ion are: Na= 0-1000ppm K= 0-1000ppm Li= 0-1000ppm Ca= 10-1000ppm Ba= 30-3000ppm However, BWB Technologies do not recommend that routine measurements be used at the higher concentrations. For the best results the samples should be diluted so they are around 100ppm or less.

Matrix is the set of all the species that are present. Some of them we want to measure, some of them interfere with what we want to measure, and some of them are in the background that may or may not affect our results. For example, wine samples have alcohol in them. We know that alcohol will affect the flame which in turn affects the results so we want to add alcohol in our standards to try to get the standards to have a similar matrix as a sample. Now, the wine also has other things in it like colorants, flavors, and bits of grape peels. Those would be much harder to add in the correct amount and I'm not sure that they would've interfered very much anyway so I choose to not add them to my standards matrix

The Diluent Concentrate does not need to be used with all samples. It is a non-ionic surfactant that is used to adjust the surface tension. You may see a slight increase in signal because the drops in the mist will be smaller so more make it to the flame. Its real use is when samples have materials that affect the surface tension, like alcohols, proteins, oils, or fats. Using the Diluent Concentrate in the samples and standards will help to make the surface tension the same with both to give better results. If the samples are simple salt solutions it is not needed at all. It is very important to use good DI water and I see that you are doing so with an exchange resin bed.

These appear to be blood serum samples. Yes, they can be detected easily by the BWB-XP. However, they will need to be diluted. Most users dilute by 100:1. Therefore, the standards will need to be made to the diluted values to calibrate. Before calibrating, set the units to mmol/l under Setup/Ions/Next Calibration. There are two options that can be done with the calibration at this point. Use the diluted values (1.40 mmol/l, 0.051mmol/l) and remember to multiply by 100 to get the final results. Tell the instrument that the diluted standards are the concentrations before diluting. Then, they can read the final results directly. The first option will be more precise. The second option is easier and will probably give results within the tolerance they want.

First, it depends on the nature of the sample. If the concentrations are more than about 100ppm they would want to dilute before aspirating. Higher concentrations of salts will form deposits inside the mixing chamber and burner. They would need to be cleaned often which would cause them to take the instrument off-line. That could be as often as every hour at 1000ppm. Another issue is the environment where they would situate the instrument. Process facilities are generally dirtier than laboratories. Any dust or smoke in the air will be drawn in and cause instability of the readings. Temperature is also an issue. Will the ambient temperature change during calibrations and readings? If so, that could further muddle up the situation. We have an option of a Collection Cup. The sample is pumped to the collection cup where it is aspirated into the instrument.

In general, the BWB-XP flame photometer can be used for sewage water. However, there are some issues that will need to be dealt with. Sewage water will have many unknown contents that can change hourly. Many of these will interfere with measurements. To limit the interferences the samples will need to be diluted. I recommend diluting until the Na is at 10ppm or less if possible. This may not give a high level of precision so the customer will need to develop a method that works for them. All solids need to be settled/filtered out

Any phosphate present will interfere. So either the Ca is precipitated out and re-dissolved separately or the phosphate is "tied up" so it isn't available to react with the Ca. (What happens is the phosphate and Ca form a complex that needs a different temperature flame. The Ca is no longer "available" as an element.) Here are some options. Precipitate the Ca as the oxalate and redissolve with perchloric acid. See Methods 14 and 15 in our Guide to Flame Photometry. Remove the phosphate using anion-exchange resins. (Also works on sulphate.) There are many different kinds of resins so they will need to investigate which will work and follow the manufacturers' instructions. Protect the Ca using EDTA as a chelate. All I have is a comment "large amounts of EDTA in strong KOH solutions". Protect the Ca with 1% by weight dextrose. This did not restore the full emissivity of the Ca. Add lanthanum at 5 times the molar content of Ca (after dilution).

I do not see any reason that this would not be able to be measured. It has the high pH to keep it from forming cyanide gas. However, I would recommend you use a fume hood over the chimney exhaust in case some cyanide gas forms in the flame. If so, you not only do not want to breathe it, there could be some corrosion in the chimney over time.

The BWB is a low temperature flame emission spectrometer. As such, it only measures Na, K, Li, Ca, and Ba. That is one of the main advantages for most users, as long as these are the only elements one is interested in. Most of the other elements do not interfere making the analysis much easier. The Lanthanides cannot be done.

Yes. Whatever method and equipment used the result will depend on the tolerance of the equipment and technique. It is best to use the same methods of dilution on both calibration standards and samples. Be aware of contamination.

There are two ways to do this, one is harder but it will be more exact while the easier way will not be so exact but still may be good enough for your purposes. I will use your example. Remember that the Standard Concentrates we supply are in mg/l and mg/l = ppm only at 20 Degrees C. I will assume everything is at 20 C. The hard way: Each Ba Standard will need all the concentrates added in their correct proportions. That is, for the 50ppm add 0.5ml Ba, 0.3mlNa, 0.3ml K, 0.2ml Ca and dilute to 100 ml total with DI water. For the 60ppm add 0.6ml Ba, 0.3ml Na, 0.3ml K, 0.2ml Ca and dilute to100ml. Continue in the same manner with the others. The easier way: Make a large batch (1 liter) of a diluent solution that is 30ppm Na (3ml), 30ppm K (3ml), 20ppm Ca (2ml) diluted to1000ml with DI water. Let us call this solution 30/30/20. Then use this 30/30/20 solution to make each Ba Standard. That is, for the 50ppm add 0.5ml Ba and dilute with the 30/30/20 solution to 100ml. Similar with the others. This method will have the background ions vary by 5-10%. Most of the time that will be OK. Another reason to go with the easier way is when compensating for background ions, like in this situation, it is best to use the 30/30/20 solution as the Blank. So, it would need to be made anyway. If the 5-10% variation is OK it saves a good bit of work. I see a possible problem with what you have here. The Ca will interfere with the Ba. That is, the Ca spectrum has a component where the Ba is measured. The Ca signal may be larger than the Ba signal and it will not be seen. If your flame is maximized for Ba the Ca signal may be lessened.

We supply 10,000 mg/l calibration solutions that can be made into these. For all these solutions the ions in question are all single valence so mEq/l is the same as mmol/l. To convert mmol/l to mg/l, multiply by the atomic mass. For example, the Li=15mmol/l (same as 15mEq/l) is multiplied by 6.94g/mole giving 104.1 mg/l. To make this from our solutions it is easiest to use the equation V1xC1=V2xC2. If you want 500 ml of 104.1 mg/l that would be 0.500 liter x 104.1 mg/l = X x 10,000 mg/l. Solve for X = 0.0052 liter. So take 5.2 ml of the 10,000 mg/l solution and dilute to 500 ml.

Question: My greater question was if the output dilution rate of 1:200 was in the normal range of the BWB instrument. Our solutions are between 2 and 170 mmol/l in Sodium concentration. After the incoming Na concentrations to the photometer are between 0.01 and 0.85 mmol/l. If I have done my math correctly this would be a concentration range of 0.23ppm to 19.6ppm. I believe this is within the BWB photometer's specifications. I do possibly have the option to dilute at a rate of only 1:50 if need be. Answer: A 200:1 dilution is very good for the BWB-XP. Your calculations are correct, and you will be in the best range for measuring Na with a single point calibration which makes things easy.

The key to most biological samples is to dilute sufficiently to lower the interferences. If the Na in mouse urine is ~200meq/l I would dilute by at least 200:1. The higher the Na concentration the more dilution. Get it so it is around 1meq/l or less. (Of course, multiply the reading by the dilution factor to get the original concentration.) You are correct to do a multiple point calibration, even at lower concentrations, to get the best results. To help mitigate the action of urea you can do matrix compensation techniques. When making your calibration standards, add urea to your diluent solution at a concentration close to what the urea will be in the diluted samples. With urea at the same concentration in all the standards and test samples it will have the same effect on them all and you will be "compensated" for its presence. Urine can have other chemicals, like proteins, so it will help to make your diluent solutions with the Diluent Concentrate (surfactant). Also, to lessen build up of proteins, urea, etc., use a solution containing the Decon 90 often to clean out the Nebuliser and mixing Chamber, especially after you are done using for the day. Run it for about 20 minutes before shutting down the flame

Our flame photometer uses about 1-2 ml of final sample to get a reading. That is 10x what your customer is doing now. However, their concentrations of Na and K will need to be diluted for best results. The Na should be diluted by 100x or 200x. The K can be diluted by 10x. Both of these will bring the final volume where a measurement can be made. The Li will be a bit low concentration at a 10x dilution but may still be okay.

Yes, it is made of NaOH. It sounds like after using it for the day they aspirate Decon 90 solution. In my experience, that will not clean it out properly. The parts need to be taken off the instrument and cleaned using a brush with stiff bristles, like a tooth brush. Rinse it very well with DI water and allow to dry before assembling. The Decon 90 has many chemicals in it. It should be diluted to 2-5% in DI water. If you want to read more about the Decon 90 their web site is www.deconipa.com. A solution of the Diluent Concentrate can be use at the end of the day for about 20 minutes. It will help to clean out the system but it is not a substitute for thorough cleaning.

We are familiar with the Instrumentation Laboratory instrument. The pharmaceutical use of the IL is for measuring blood plasma and urine. These samples need to be diluted by 100 to 1. Therefore, a 20 µL sample then becomes 2000 µL or 2 mL. We aspirate at about 3 mL per minute. Most readings stabilize within about 15 to 20 seconds so 2 mL can be measured using the BWB. Almost all the time, samples will need to be diluted. How much will depend on the actual sample. Even for industrial users with valuable samples will probably need to dilute also. Always keep in mind that flame photometry works best at lower concentrations. There is less self absorbance and interferences are minimized.

Questions: 1. The customer’s samples include serum, urine, sweat, drink (soda/milk) can you confirm they can be used with your flame photometer? 2. What is the range of detection (min to max) for Na, K, Li, Ca, Ba? 3. What is the maximum number of calibration points which can be taken in multi-point calibrations? 4. Does the BWB Technology Flame photometer series have any safety feature? (For example, automatic gas shut off) 5. What is the gas flow rate, and can it be altered? 6. What reagents and equipment must a customer purchase? 7. The system comes with gas regulator. Is it for connection to the gas cylinder? 8. What is the main difference between Flame AAS and Flame AES? Answer: 1. These items certainly can be analysed with flame photometry. These were some of the first materials analysed when it was invented over 70 years ago. These samples will need some form of preparation (dilution, breakdown of proteins, etc.) prior to running through the instrument. The literature is rife with various methods for preparation, and we have some of them in our Guide to Flame Photometry. Your customers will need to determine what preparations are needed for their samples. 2. The limits of detection (where the signal is not distinguishable from Blank) are. Sodium Na= 0.02ppm Potassium K= 0.02ppm Lithium Li= 0.05ppm Calcium Ca= 1.0 ppm Barium Ba= 10ppm The maximum levels, for practical reasons, should not go much above 100ppm. Experience has shown that high ppm levels will require cleaning of the Mixing Chamber and Burner Tube often. At 1000ppm they might need to be cleaned every hour. This is one of the main reasons that dilution of samples needs to be done. 3. Multi-point calibrations can be done with 14 points (plus Blank) for each ion. 4. Yes. There is a flame detector and a solenoid that will shut off the fuel gas if the flame goes out. Another safety feature is the Level Sensor that ensures the U-Tube is filled before starting. There is a gas/air mixture that is flammable and if the U-Tube is not filled, that mixture can escape outside causing a potential fire hazard. 5. The air flow rate is fixed that the user can not adjust. The gas flow rate is adjustable to tune the flame height. It is about 0.4 litres per minute. 6. Customers can purchase our Fluids Kit that contains concentrated calibration standards for all 5 ions, diluent concentrate, and Decon 90 cleaning concentrate. If they want, they can also get our Starter Pack that has all the items in the Fluids Kit as well as pipettes, flasks, and sample cups. 7. The supplied gas regulator does not go on the gas cylinder but is fixed on the back of the instrument. It will handle the pressure straight from propane, butane, or LPG cylinders (20Bar or less). The user needs to provide a hose connection at the cylinder for attachment to the provided hose. They will just use the shut-off valve on the cylinder to provide or turn off the gas. There are some things to ensure precise results. a. Clean the Mixing Chamber and Burner parts often. b. Keep the samples diluted to 100ppm or less. c. Do a multi-point calibration bracketing the expected concentration of the sample. d. Use the same techniques to calibrate and measure samples. Use the same size sample cups filled to the same level and place them in the same spot on the spill tray. Do not hold by hand. 8. There are quite a few differences between FP AES and FP AAS spectrometry. Both introduce the ions into the flame where they are put in an excited state. With AES, as the excited state "relaxes" it emits light of a specific colour which is then detected. The more light detected the more ion is in the sample. With FP AAS, the excited state will absorb certain colours. A white light containing all colours is passed through the flame and the excited ions will absorb certain colours. The degree of absence of those colours is a measure of the concentration in the sample.

Question: I want to determine the level of lithium in blood serum using flame photometry, please advise whether you have calibration standards in units for biochemistry (mmoles, etc.) supplied with the BWB XP flame photometer? Answer: Our standards that you receive are of concentrations of 10,000ppm. To convert ppm into mmol/l, divide the value in ppm by the atomic mass of the ion in question (6.94 for Li). When diluting the Standard Concentrates in ppm to mmol/l be sure to do so at 20°C

Question: For bio diesel, we want to measure K and Na for bio diesel if possible. Could we measure it using the BWB-XP flame photometer? Answer: It depends on what stage of production the customer wants to measure. The actual biodiesel cannot be run through the instrument. It will attack several of the components and will change the flame temperature. He probably wants to measure the waste portion to make sure the Na and K compounds are fully washed out. Many of these are soap-like compounds and are washed out with water. As long as measurements toward the last of the wash so there is not much "soap" it should be OK. The first of the wash would have too much "soap" and would foam inside the Mixing Chamber causing erratic readings.

Answer: That level of sulphuric acid (H 2 SO 4 ) would be acceptable to use with the BWB Technologies Flame Photometer.

Answer: Even at low concentrations Hydrofluoric acid should not be used. It will attack the stainless steel capillary on the Nebuliser and Burner, the silicone U-Tube/Waste tubing, the Level Sensor, and the glass Drain Cup. It might take some time to cause a failure of these components at low concentrations but it will happen eventually. The use of HF will void the warranty.

Question: Is this instrument suitable for the analysis of Lithium and Barium in Iron Oxide samples? Answer: This application has some difficult issues. First is the wide range they are looking at. It is not practical to run samples that are high in salt concentrations. More than a few hundred ppm and the salts deposit on the insides of the mixing chamber and burner. They will then come off erratically and the readings will be very unstable. Therefore, the mixing chamber and burner will need cleaning often. To avoid this, keep the concentrations at 100ppm or below. The lower concentrations will be acceptable to use but the higher concentrations will be a problem. BWB Technologies does not recommend running at concentration levels above 2000ppm which could easily be possible with this kind of sample. If the user knows their samples are of low concentration, they may not need to dilute them and if they know they are of high concentration they can dilute them accordingly. If they have no idea what the concentration is before they start it will be much more difficult. The next issue is that almost everything in this system will interfere with each other at higher concentrations. Another reason to dilute the samples is that Iron in the presence of Lithium at dilute levels (30ppm) starts to depress the Li response. Barium also influences Li but is not too significant under concentrations of 300ppm. The acids will also have an effect. Keep hydrochloric under 0.03 M and the sulphuric under 0.1M (when the samples are diluted). Barium- Iron has a very strong interference and should be absent when analysing samples. The sulphuric acid will depress the response, but it is not known how much this will influence the results. The hydrochloric is acceptable up to 0.1M. Due to the user is measuring in iron oxide samples the iron will be too high even if they dilute the sample massively. To get the iron dilute enough to where it will not interfere with the Ba and Li being too low. Therefore, the user will probably need to precipitate out the iron. It is possible that they are already doing this, and it will not be a problem. An alternative is to remove the Ba (as a precipitate) and Li (using ion exchange resins) from the samples, re- dissolve and then measure them separately. This will keep them all apart and they will not interfere so the matrix compensation will not need to be accounted for. The interferences between the Ba and Li can be dealt with through matrix compensation techniques. That is, when making up calibration standards for each ion the other ion needs to be at the same concentration expected in the sample. For example, if the Ba is 100ppm and the Li is 20ppm all the Ba standards will have 20ppm Li and all the Li standards will have 100ppm Ba. If the acid concentrations are a bit high, they can similarly be compensated for in the matrix.

Question: The sample to be measured is a polymer. The sample is a diluted liquid state of polymer with a NaOH solvent and the concentration of it is about 24-25%. The client wants to measure the concentration of Na of this sample. According to the customer, it is difficult to measure Na by reason of high concentration; it can be diluted with DI water. Answer: The sample will need to be diluted. At 25% NaOH that is 250g/l or 144g/l of Na. Doing a 1000:1 dilution (1ml diluted to 1 litre) gives 144mg/l Na. This would be the minimum dilution needed. It would be better to dilute an additional 10 times (10,000:1 or 0.1ml diluted to 1 litre) to give 14.4mg/l. That will put them in the range where the Na has very little interferences. However, there could be a problem with the polymer portion. If the polymer does not precipitate out when diluting it could clog the nebuliser or coat the mixing chamber. Both would then need to be cleaned very often.

Answer: All five ions are displayed although only four can be seen at a time because the display is only four lines. There is an issue with Ba; there cannot be any Ca present when measuring Ba due to interference. The other ions will interfere with each other at concentrations above 100ppm. The samples will need to be diluted to avoid these interferences to a level of at least 100ppm.

Answer: At high concentrations of Na, I recommend that the sample is diluted by a factor of 10:1, minimum. That will put it in a good range and much of the instability will not happen. What happens is that the salt will build up on the inside surfaces of the Nebuliser, Mixing Chamber and Burner. It gets into the microscopic pores and then will come out at random times and reaches the flame. At 500-900ppm that could only take a couple of hours or less. Dilute by 10:1 and it may take several days. If they were to dilute by 100:1 it could take weeks if it happens at all. BWB Technologies recommends using concentrations under 100ppm for samples and standards. It sounds like after using it for the day they aspirate either Decon 90 or HNO 3. In my experience, that will not clean it out properly. The parts need to be taken off the instrument and cleaned using a brush with stiff bristles, like a toothbrush. Rinse it very well with DI water and allow drying before assembling. If they can dilute like I mentioned, they can do a rinse by aspirating DI water through at the end of the day for about 20 minutes. It also helps to run DI when not testing samples. The Decon 90 has many chemicals in it. It should be diluted to 2-5% in DI water. If you want to read more about the Decon 90 their web site is www.deconipa.com.

The sample concentrate which user is detecting is below: Na : 3218.39 ± 34.48ppm (equals to 140.0 ± 1.5mmol/L) K : 196.47 ± 5.88ppm (equals to 5.01 ± 0.15mmol/L)

Accuracy is dependent on many factors, so it is difficult to give an exact number. During final testing when we build them, we look for 1% or better. This is with simple salt solutions which are easier to achieve high accuracy with than serum due to serum having a complex matrix. Most users with these samples are happy to achieve within 5% accuracy which they can do well with the BWB-XP.

It is difficult giving you a definite number. The results are dependent on many factors like the nature of the samples and operator technique. With simple salts diluted down to less than 100ppm we routinely get within 1%. Most samples are not simple salt solutions and have many other components that can complicate the measurement. First, there are two things to know before starting. 1. We provide standards at a nominal value of 10,000 mg/l. They are not exactly 10,000 mg/l but we provide the Certificate of Analysis that gives the tested value of each batch. For example, the actual value may be 9,980 mg/l. This is the number that should be used to be the most accurate. For my discussions here I will use 10,000 mg/l for ease of use. 2. Again, to be the most accurate all solutions and volumetric ware should be at 20 degrees Celsius. Note that mg/l is the same as ppm only at 20 degrees. Slight deviations from 20 degrees will not alter the results by much but it is much more difficult to factor it in. Most users do not need to be that precise and, most of the time, flame photometry is only good to three significant figures or less. The general formula to use when diluting is: (Concentration 1) x (Volume 1) = (Concentration 2) x (Volume 2) So, if I start with a 10,000mg/l solution and want to make 100ml of a 100mg/l solution I set up my formula as: (10,000mg/l) x (X) = (100mg/l) x (100ml) Solve for X = 1ml This means that taking 1ml of the 10,000mg/l and dilute it to 100ml will give me a 100mg/l solution. Remember the actual value can be different so, from my example above, you would get a 99.8mg/l solution. If you wanted an exact 100mg/l solution you would use 9,980 mg/l in the formula and you would need to measure out

Question: I would like to ask how to prepare Ba standards which also have other ions in it, for example: 50ppm, 70ppm, 80ppm, 90ppm, 10ppm Ba standards which also have Na 30ppm, K, 30ppm, Ca 20ppm in it? Answer: There are two ways to do this, one is harder, but it will be more exact while the easier way will not be so exact but still may be good enough for your purposes. I will use your example. Remember that the Standard Concentrates we supply are in mg/l and mg/l = ppm only at 20°C. I will assume everything is at 20°C. The hard way: Each Ba Standard will need all the concentrates added in their correct proportions. That is, for the 50ppm add 0.5ml Ba, 0.3ml Na, 0.3ml K, 0.2ml Ca and dilute to 100 ml total with DI water. For the 60ppm add 0.6ml Ba, 0.3ml Na, 0.3ml K, 0.2ml Ca and dilute to100ml. Continue in the same manner with the others. The easier way: Make a large batch (1 litre) of a diluent solution that is 30ppm Na (3ml), 30ppm K (3ml), 20ppm Ca (2ml) diluted to1000ml with DI water. Let us call this solution 30/30/20. Then use this 30/30/20 solution to make each Ba Standard. That is, for the 50ppm add 0.5ml Ba and dilute with the 30/30/20 solution to 100ml. Similar with the others. This method will have the background ions vary by 5-10%, most of the time that will be OK. Another reason to go with the easier way is when compensating for background ions, like in this situation, it is best to use the 30/30/20 solution as the Blank. So, it would need to be made anyway and if the 5-10% variation is OK it saves a good bit of work. I see a possible problem with what you have here. The Ca will interfere with the Ba. That is, the Ca spectrum has a component where the Ba is measured. The Ca signal may be larger than the Ba signal and it will not be seen. If your flame is maximised for Ba the Ca signal may be lessened. Question: If the Ba concentration is higher, will it be easier to measure? If yes, can we double the grams of solid to dissolve in the water to obtain the sample with 2 times higher in concentration (about 140 - 180 ppm)? We currently use the popular LPG (use in kitchen) for the flame. Is this fuel ok to use? Answer: Doubling the concentration of the Ba will make it a bit easier but without the cooler flame it probably will not be enough. LPG is a mixture of mostly propane and butane with some other hydrocarbons present; it does burn cooler than propane. Keep the flame setting as cool as possible and you might be OK.

In general, the BWB-XP flame photometer can be used for sewage water. However, there are some issues that will need to be dealt with: 1. Sewage water will have many unknown contents that can change hourly. Many of these will interfere with measurements. 2. To limit the interferences the samples will need to be diluted. I recommend diluting until the Na is at 10ppm or less if possible. This may not give a high level of precision so the customer will need to develop a method that works for them. 3. All solids need to be settled/filtered out.

Question: I am interested in setting my BWB flame photometer to most accurately measure sodium in mouse urine. I was going to set up a multipoint calibration with different concentrations of sodium, and I read that the other chemicals in the solution could alter my calibration curve i.e., urea. What is the best way to calibrate for sodium in mouse urine? Answer: The key to most biological samples is to dilute sufficiently to lower the interferences. If the Na in mouse urine is ~200meq/l I would dilute by at least 200:1. The higher the Na concentration the more dilution. Get it so it is around 1meq/l or less. (Of course, multiply the reading by the dilution factor to get the original concentration.) You are correct to do a multiple point calibration, even at lower concentrations, to get the best results. To help mitigate the action of urea you can do matrix compensation techniques. When making your calibration standards add urea to your diluent solution at a concentration close to what the urea will be in the diluted samples. With urea at the same concentration in all the standards and test samples it will have the same effect on them all and you will be "compensated" for its presence. Urine can have other chemicals in it, like proteins, so it will help to make your diluent solutions with the Diluent Concentrate (surfactant). Also, to lessen build-up of proteins, urea, etc., use a solution containing the Decon 90 often to clean out the Nebuliser and mixing Chamber, especially after you are done using for the day. Aspirate a mixture of 5% Decon 90 to 95% DI water for about 20 minutes before shutting down the flame. This will help to reduce build-ups in the mixing chamber which can heavily influence reading stability.

Question: Our samples are NPK + Ca Fertilizer and our Ca does not give the correct reading because of the interference of Phosphate present in the sample. What is the method for analysing Ca using the BWB XP flame photometer with this type of sample? Answer: Any phosphate present will interfere. So, either the Ca is precipitated out and redissolved separately or the phosphate is "tied up" so it isn't available to react with the Ca. (What happens is the phosphate and Ca form a complex that needs a different temperature flame. The Ca is no longer "available" as an element.) Here are some options. 1. Precipitate the Ca as the oxalate and redissolve with perchloric acid. See Methods 14 and 15 in our Guide to Flame Photometry. 2. Remove the phosphate using anion-exchange resins. (Also works on sulphate.) There are many kinds of resins so they will need to investigate which will work and follow the manufacturers' instructions. 3. Protect the Ca using EDTA as a chelate. The process by which EDTA annuls the effect of phosphates is due to EDTA having a very high relative bond enthalpy to calcium ions in solution, much greater than that of Calcium Phosphate complexes; however, does not change the emission range of light waves. 4. Protect the Ca with 1% by weight dextrose. This did not restore the full emissivity of the Ca. 5. Add lanthanum at 5 times the molar content of Ca (after dilution)

Question: I want to measure a concentration of Potassium in KCN (Potassium Cyanide) and KOH (Potassium Hydroxide) solution. Is it possible to measure it? Answer: I do not see any reason that they would not be able to measure this. It has the high pH to keep it from forming cyanide gas. However, I would recommend you use a fume hood over the chimney exhaust in case some cyanide gas forms in the flame. If so, you not only would not want to inhale it but there could be some corrosion in the chimney over time.

The main differences are in the calibration curves. The BWB-XP and BWB-XP Plus can be calibrated up to 10 points (plus Blank) per ion. Once calibrated, it will hold that calibration until it is erased or corrected by the user. The calibration can be accessed by the operator at any time. The XP plus has an additional feature the XP does not. It has an Internal Reference System where the operator has a choice to use either Li or Cs and an internal standard. It will make adjustments for small changes due to flame conditions or drifting. In order to accommodate this, the Ba has been removed. For the BWB-BIO there are a total of four curves that can be calibrated up to 5 points (plus Blank) for each ion. These curves are first split between Serum and Urine. Thye are each further split between Na/K and Li/Ca. The Na/K and Li/Ca each need different dilution factors for proper measurement. The operator cannot access them without a special administration code. The Calibration Correction then becomes their only way to calibrate. Our Calibration Correction feature allows the user to adjust this original calibration curve to account for differences in flame settings with just one calibration standard solution (the highest one used in the original calibration). Many users measuring biological samples do not want operators access to change protocols. The BIO also has the Internal Reference System. Our most recent addition is the BWB-BIO-943. This was meant for users who are familiar with the Instrumentation Laboratories 943 flame photometer. It has two calibration curves, the Serum and Urine with Li enhanced so it can be included with the Na/K. Ca has been eliminated.

There are quite a few differences between FP and AA spectrometry. Both introduce the ions into the flame where they are put in an excited state. With FP, as the excited state "relaxes" it emits light of a specific color that is then detected. The more light detected the more ion is in the sample. With AA, the excited state will absorb certain colors. A white light containing all colors is passed through the flame and the excited ions will absorb certain colors. The degree of absence of those colors is a measure of the concentration in the sample

Drinking water does not have high levels of dissolved salts so should be easy to measure. An XP will work fine but I would recommend the XP Plus if they do not mind using the Internal Reference, meaning needing to add either Li or Cs. It will give a bit better results. It really depends on if they are price sensitive and the lower cost of the XP will be too high.

Answer: The BWB-XP can be calibrated at 10 points per ion and once calibrated it will hold that calibration set until it is erased by the user. Our Calibration Correction feature allows the user to adjust this original calibration curve to account for differences in flame settings with just one calibration standard solution (the highest one used in the original calibration). For the BWB-BIO we will have two curves embedded that the user will not be able to erase. The Calibration Correction then becomes their only way to calibrate. Here it will use the middle solution of the curve. The curves will be for the expected range for serum (Na: 120-160 mmol/l, K: 3-7 mmol/l, Li: 0.5-2 mmol/l, Ca: 1.5-3.5 mmol/l) and an expected range for urine (Na: 25-300mmol/l, K: 25-200mmol/l, Li: 2.5mmol/l, Ca: 2.5-20mmol/l). The user will be able to switch from one curve to the other. Doing this reduces user error when forming calibration standards and increases the ease of use. With the BWB-XP it is possible to do a similar thing with only one curve but with differing precision along that curve. As an example, I'll illustrate for Na. For the urine curve of 0- 200mmol/l and using 25mmol/l increments as a general spacing but an increased resolution for the serum, say every 10. I would then recommend using the calibration standards (blank), 25mmol/l, 50mmol/l, 75mmol/l, 100mmol/l, 120mmol/l, 130mmol/l, 140mmol/l, 150mmol/l, 160mmol/l and end up with 200mmol/l. (All of these are diluted from their nominal values.) This involves a lot of work but only needs to be calibrated once. The BWB-XP is designed to be useful across many industries and can be set too many configurations that reflect what a particular user would need. The BWB-BIO is meant to be used only for these two samples and to be "dumbed down"; so the user cannot make changes. All they would do is to warm up the instrument, choose a curve, do a one point "calibration" (which acts as a calibration correction of a multipoint curve) and run their samples. Another Significant difference between the BWB-XP and the BWB-BIO is that the BWB-XP is able to measure Barium levels in samples, whereas the BWB-BIO cannot.

The BWB flame photometer can be used with biological samples. Flame Photometry was the original method used back in the 1960's when they went from wet methods to instrumentation. Most often the use is for Na, K, and, sometimes, Li. Ca measurements are problematic because the samples require the Ca to be extracted away from the rest of the constituents

Answer: There are three main differences between industrial use and instruments meant for serum and urine. The sample size is one of them. Biological samples can be much smaller, so the nebuliser needs to be configured to minimise the aspiration rate. Another difference is that the calibration curves are built-in permanently into the instrument. The BWB-XP can be used with biological samples of urine and serum. It just has not been optimised for that specific market. As an industrial instrument the BWB-XP has many options and settings allowing the user to configure it in many ways as well as the ability to measure Barium concentrations. The BWB-BIO will not have such an array of settings but will constrain the user to follow certain protocols. The reason for this is that this market wishes the user of a BWB-BIO to be unable to change those protocols.

We sometimes receive inquiries from users in the pharmaceutical field who use a flame photometer made by Instrumentation Laboratory (IL) in Italy, the model is the IL 943. This product is no longer supported and there are opportunities to replace this old instrument for a new BWB flame photometer. The one specific feature of IL flame photometer is measurement of particle sample (e.g. the minimum is 20 μl). 1. How much sample is the minimum sample requirement for the BWB-XP? 2. How do we use very small sample sizes. For pharmaceutical field research, samples are valuable due to high cost. Please let us know the unique features of the BWB flame photometer that would appeal to a pharmaceutical researcher. Answer: We are familiar with the Instrumentation Laboratory instrument and the BWB flame photometer is an ideal replacement for customers who are looking to upgrade. The pharmaceutical use of the IL is for measuring blood plasma and urine. These samples need to be diluted by 100 to 1. Therefore, a 20 µl sample then becomes 2000 µl or 2 ml. We aspirate at about 3 ml per minute. Most readings stabilize within about 15 to 20 seconds so 2 ml can be measured using the BWB XP. I theorise that there are other pharmaceutical users that want to measure solutions other than plasma and urine. Almost all the time the sample will need to be diluted. This is dependent on the actual sample. Even for industrial users with valuable samples will probably need to dilute their samples, keep in mind that flame photometry works best at lower concentrations. There is less self-absorbance and interferences are minimized at these low concentrations.

The limits of detection (where the signal is not distinguishable from Blank) are: Sodium Na= 0.02ppm Potassium K= 0.02ppm Lithium Li= 0.05ppm Calcium Ca= 1.0 ppm Barium Ba= 10ppm The maximum levels, for practical reasons, should not go much above 100ppm. Experience has shown that high levels will require cleaning of the Mixing Chamber and Burner Tube often. At 1000ppm they might need to be cleaned every hour. This is one of the main reasons that dilution of samples needs to be done.

The air flow rate is fixed. The user can not adjust.The gas flow rate is adjustable to tune the flame height. It is about 0.4 liters per minute.

Yes, the calibration standards are provided with Certificates of Analysis and Safety Data Sheets

Answer: Na : 0.02ppm = 8.7 x 10-4 mmol/L K : 0.02ppm = 5.1 x 10-4 mmol/L Note: These limits of detection are in the best of circumstances. Not all users will be able to achieve them.

Accuracy is dependent on many factors so it is difficult to give an exact number. During final testing when we build them we look for 1% or better. This is with simple salt solutions which are easier than serum. Most users with these samples are happy to achieve within 5% which they can do well with the BWB-XP.

It is difficult giving you a definite number. The results are dependent on many factors like the nature of the samples and operator technique. With simple salts diluted to less than 100ppm we routinely get within 1%. Most samples are not simple salt solutions and have many other components that can complicate the measurement. First, there are two things to know before starting. 1. We provide standards at a nominal value of 10,000 mg/l. They are not exactly 10,000 mg/l but we include the Certificate of Analysis that give you the tested value of each batch. For example, the actual value may be 9,980 mg/l. This is the number that should be used to be the most accurate. For my discussions here I will use 10,000 mg/l for ease of use. 2. Again, to be the most accurate all solutions and volumetric ware should be at 20 degrees Celsius. Note that mg/l is the same as ppm only at 20 degrees. Slight deviations from 20 degrees will not throw off the results by much but it is much more difficult to factor in. Most users do not need to be that precise and, most of the time, flame photometry is only good to three significant figures or less. The general formula to use when diluting is: (Concentration 1) x (Volume 1) = (Concentration 2) x (Volume 2).So, if I start with a 10,000mg/l solution and want to make 100ml of a 100mg/l solution I set up my formula as:(10,000mg/l) x (X) = (100mg/l) x (100ml)Solve for X = 1ml. This means that taking 1ml of the 10,000mg/l and dilute it to 100ml will give me a 100mg/l solution. Remember the actual value can be different so, from my example above, you would get a 99.8mg/l solution. If you wanted an exact 100mg/l solution you would use 9,980 mg/l in the formula and you would need to measure out 1.002ml. Rather than trying to measure 1.002ml, when the instrument is calibrated you can enter 99.8

Start with graph paper (a grid layout). Along the bottom axis indicate your concentrations of each of the calibration solutions, keeping them properly spaced. For example, Blank (0ppm), 25ppm, 50ppm, and 75ppm would be equally spaced at whatever distance you choose. Along the vertical axis you will put the Raw readings. First find out what they are and write them down, so you know how to space them. When you look at the Raw readings, they can get quite large and you will see them changing. It is best to round them off to the first three or four numbers. For example, 31,245 would be rounded to 31,200 and 31,278 would be 31,300. Use these set of numbers to space your indications on the axis keeping the proportions between them. Find the intersections of each concentration and its Raw reading and put a dot there. When all of them are done draw a smooth curve connecting the dots as best you can. You do not need to go exactly through each dot. The best curve you can draw that is smooth and gets as close to all the dots as you can. When calculating the concentration of samples take the Raw reading and find it on your vertical axis. Go across the graph until you intersect the curve. At that intersection go straight down to the bottom axis, read the concentration on the bottom axis. You will need to figure out how far from your known concentrations to get the concentration of the sample. For example, if it falls halfway between 25ppm and 50 ppm it is 37.5ppm. If you need more detail, there are many sources on-line or in mathematics textbooks. From this there is also a visual representation of how calibration standards having more increases the precision of the calibration graph.

They will probably want our Fluids Kit that contains concentrated calibration standards, diluent concentrate, and Decon 90 cleaning concentrate. Individual solutions are also available. We also have available an Annual Service Kit and a Preventative Maintenance Kit.

The Decon 90 is a non-ionic surfactant. Other cleaning products will work as long as they are non-ionic. The ionic types usually have a Na salt of various aliphatic sulfonates or sulphates. When trying to clean them with ionic types, the Na deposits on the inside surfaces and makes it dirtier! The non-ionic types use ethoxylated alkyl phenols, fatty acid amides, or polymers of oxides and thus have no ions to accumulate inside the burner/mixing chamber.

The adjustment on the nebuliser should never be changed. At the present time it is too difficult to explain the process to re-set it. We are working on a method for users but it is not ready. If it has been changed it is best to replace it.

De-proteinizing solution is any cleaning agent that works well cleaning off proteins. Decon 90 is one of these types of cleaning agents that we provide. Proteins in samples can clog the capillary tube on the nebuliser and, with extended use, form a coating in the mixing chamber and burner tube where they can affect the results.

It depends on the nature of the samples and the frequency of use. Simple low concentration salts samples will not require as much cleaning. Samples with high concentrations and/or proteins or oils will need cleaning quite often. A general rule is, if there are problems getting good readings, the first thing is to suspect the instrument needs cleaning. It helps to aspirate DI water or a solution of the Diluent Concentrate diluted at 1-2% after done with a run of samples.

Yes, a correction at a minimum and full calibration of readings prove not to be accurate enough.

Blank is point 0- so it is blank + a max of 10 points of calibration (it may be necessary to do 10 points- trial and error will tell).

Decon is for cleaning, it contains high concentration of Na and should never be added to samples. Diluent concentrate (Brij35) is an organic surfactant and helps to achive more repeatable results- it can be added at a rate of 1-2ml per Ltr.

No. the best course of action would be to estimate the likely range of the readings expected and calculate the ratios of the average of each of the ion ranges, then make calibration standards in approximately those ratios. ie. based on the single example you gave, there was approx. 3 times as much Na as K so, if diluting by 1:125, make your highest standard with say 1000 ppm Na and 300 ppm K (similarly with Li and Ca but maybe use a minimum of 10-20ppm of Li and Ca to give a reasonable range) and then dilute that down further to give you your other standards as required. There is no point in calibrating Li at 1000 ppm if you are only ever going to measure < 10 ppm. There will always be some cross -sensitivities between ions and with such high concentrations these may be a source of too much error. The above approach will help to reduce those errors to acceptable levels.

The sensitivity of the Ca channel seems to be approx. 480 counts per ppm. You will need to compare this figure with the variation in raw count you get when taking consecutive readings on the same sample- if the ratio (sensitivity/variation) is too low then it will be difficult to make acccurate Ca determinations. After calibration it is necessary to do a correction of Ca for the effects of Na as per page 30/31 of the XP-Plus manual.

An issue we have had is that the response curve has flattened out at high concentrations so the system is inherently less accurate. With the BIO model we overcame this aspect by splitting tests into 2, Na / K and Li / Ca and having 2 different dilution ratios 1:100 / 1:10. When running the Ca / Li tests at 1:10 dilution the Na in the samples was in fact 300 - 400ppm and this seemed to work OK. I suggest to adopt a similar approach - it does mean more tests and probably means more burner cleaning but it may be a way around the issue.

The sample I wish to analyse is a brine wastewater from natural sources (deep underground). There are two different streams with main components shown below. Stream #1 - typical levels of barium are 5,000-15,000 mg/l. There is also typically the following, but range can vary beyond numbers below: Ca: 5,000-40,000 mg/l Na: 10,000-60,000 mg/l Sr: 1,000-8,000 mg/l Cl: 20,000-200,000 mg/l Other ions typically found in a brine water solution such as - carbonates, potassium, iron can also have low levels of organics resulting in high TDS, which can be up to 300,000 mg/L Stream #2 - Similar to above but Barium typically 1 - 200 mg/l

These brine samples pose a problem. They cannot be run through the flame photometer directly. The salt content is too high and salt deposits will form in the Mixing Chamber and Burner in a matter of minutes. Once they are there, they will throw off particles that will create a very noisy signal. Another reason is the interferences are huge and make it very difficult to compensate for them. Normally, higher salt concentrations are diluted down to relieve those situations. However, with these, to get the salts down enough the Ba will be diluted too far to get a reading. I think the only way to approach this is to precipitate the Ba (as the sulphate) away from the rest of the salts and re-dissolve (with ammonia EDTA) and then analyse them separately. The Barium Sulphate is 1000 times less soluble than the Strontium Sulphate and 100,000 times less than Calcium Sulphate so they should not be too much of a problem as long as there is not much of an excess sulphate added. This scheme will help with Stream 2. The Ba in samples from Steam 2 is very low but can be magnified through the precipitation/re-dissolution process. For example, if it is 100mg/l in the sample and you precipitate from one litre you will get 100mg of Ba. Re-dissolve into 250ml will give you 100mg/250ml or 400mg/l, four times as concentrated. Remember to back calculate for the original sample concentration. If you want to measure the other ions remaining after precipitating the Ba the sample can be diluted now and measured directly. I would recommend a 1,000:1 dilution factor. Ions will absorb certain colours; the degree of absence of those colours is a measurement of the concentration in the sample.

Since the Na is very strong in comparison with Ca the effects of cross- sensitivity on Na is very small and can generally be ignored. However, the influence of Na on Ca can be substantial. For determination of Ca in the presence of Na a correction is carried out by the BWB-XP firmware to take account of the overlapping  spectra. During Ca measurment a value is deducted from the Ca signal dependent on the Na signal. The scale of this adjustment is determined and stored in an internal parameter during a correction procedure. Method: 1. Perform single or multi-point/multi-ion calibrations with a mixture of Na and Ca in the ranges of interest. For example, if the client wishes to detect Ca at 10, 20 and 30ppm and the Na levels are at 100ppm throughout all of the samples, make a calibration standard at 3 different cencentrations including 100ppm of Na in each. If however, the Na is variable then vary this within the standards accross Ca calibration points too, for example: Point 1 Ca 10ppm Na 5ppm, Point 2 Ca 20ppm Na 15ppm, Point 3 Ca 30ppm Na 30ppm. 2. Perform a correction for Ca due to Na. Aspirate a solution containing only Na at a concentration approx. in the middle of the range of concentrations that are expected in the samples, if we use the first example above 50 ppm Na would be the approximate middle whereas the second example would be 17ppm. The correction of Ca for Na is located at: Calibrations>Correct>Correct Ca for Na (service mode must be off).

Please see HERE for Internal Reference Standard document.

Example: The client often measures high concentrations of Sodium (Na) and Potassium (K). Generally they are measuring the diluted sample with DI water. The problem is; after calibrated using standard solutions 500ppm and 1000ppm for Na and K on multi mode, measuring the standard solution again to confirm the accuracy, normally it will display a little bit high, about 5% higher than standard solution. The next day, measuring the same standard solution it will display too low, in case of 500ppm, it shows about 400-420ppm. In spite of using the same standard solution, what is the reason the results change during that time? Do we calibrate the instrument every day before measuring the sample? Answer: First, I think your customer needs to dilute even further. I suggest they dilute to 50-100ppm or further down. They should get better results because the Na and K will not interfere with each other so much and it will limit salt build up in the Mixing Chamber and Burner that can cause instability. There are many things that affect the calibration. It can change hourly or throughout the day. The next day it can be off by quite a lot. Recalibration is needed often but we have added a feature to make this situation easy for the user. We call it Calibration Correction. It can be used on both single point and multi point calibration. I will give you an example of how it works. Start by doing a multi point calibration at Blank, 25, 50, 75, and 100ppm. At a time later check the calibration by running the 100ppm standard (the highest concentration standard) and it reads something like 90ppm. Then use the Calibration Correction function. While running the 100ppm standard tell the instrument to correct back to 100ppm. The whole calibration curve inside the instrument is adjusted. There is no need to run all the standards. Here is how to use the Calibration Correction. It can only be used when there is a calibration for that ion. Go to the Calibrations Menu or key the Calibration button.Go to Edit Calibration. Choose which ion you want to edit. Key the number of the ion on the display. There is an option to do Multi correction. You will now see a menu where you can Delete, Correct for Maximum, or Correct for Blank. To correct for Maximum run the highest concentration standard used in the original calibration and key accept. To correct for Blank use the original Blank solution. You have now corrected the calibration. The calibration can be re-corrected many times and the correction can be deleted without deleting the original calibration. With a bit of practice through the menus it becomes very easy to correct the calibration so it can be done as often as needed.

Does that mean all the calibration points will be corrected automatically on the BWB Flame Photometer, when correcting max only or both correcting blank or max? The Blank is corrected by itself. Does it mean absolutely we cannot correct an individual point between blank to max? You cannot correct one of the points in between. When doing the Max correction all the points, except the Blank, are corrected at once. The "Edit Calibration" menu is where you go to do the calibration correction. First it asks which ion you want to edit. You can choose one or more ions or, if you have a Multi calibration, you can choose to do all of them with one key stroke. Additional answers: How about menu "edit calibration", what would be the effect on doing so?

Without the details of the calibration and sample measurement, proper analysis is not possible so we have to rely on guesswork. The excess Ca concentration measured was 14,700 ppm with a Na concentration of 90,000 ppm, This would suggest a cross-sensitivity of ~ 16% ie. every 100 ppm of Na generates a false Ca concentration of ~ 16 ppm due to cross-sensitivity. (This is quite feasible and can be a lot higher) The ratio Na : Ca is 1:1 for calibration but 184:1 for the sample so the effects of Na on Ca will not be compensated for in the calibration process. To measure Ca in the presence of Na it is necessary to do a correction for Na as per page 30 / 31 of the XP-Plus manual. It is also a good idea to make the calibration standards in roughly the same ratios as those expected in the samples this will compensate for the smaller cross-sensitivities that exist between the ions. Having said all that, I am somewhat doubtful that it will be possible to get an accurate measurement of Ca at such a relatively low concentration compared to Na. It would be a good idea to get a measure of the sensitivity of the Ca channel. This can be estimated by; Sensitivity = (raw reading in calibration solution - raw reading in blank) / concentration of calibration solution -> reading per unit of concentration. The lower the sensitivity the more difficult it will be to get an accurate Ca determination - a comparison of the sensitivity to the variation of reading will give the signal to noise ratio.

It is not necessary but it is good practice to do a calibration reset before doing a new calibration - start from a clean position. I have never tried calibrations with more than one 0 ppm at the start - I don't see why it should cause a problem but can't say for certain.

Hours run at Maintenance->Show Info.

Sorry - there is currently no way to change the date format on the FP.

Molarity (M) Molarity is probably the most commonly used unit of concentration. It is the number of moles of solute per litre of solution (not necessarily the same as the volume of solvent). The SI unit of molarity is mol/dm3 Molality (m) Molality is defined as a concentration of moles per unit mass. With the weight of water being 1kg per litre, molality and molarity are interchangeable, however when diluting in for example ethanol, the weight of solution is different. SI units for molality is mol/kg Parts per Million (ppm) Parts per million works as percent by mass, but is a more convenient way of expressing concentration when there is only a small amount of solute present. Therefore, ppm is defined as the mass of the component in solution divided by the total mass of the solution multiplied by 106 (one million): A solution with a concentration of 1 ppm has 1 gram of substance for every million grams of solution. Because the density of water is 1 gram per ml and if a tiny amount of solute is added, the density of a solution at such a low concentration remains approximately 1 gram per ml. Therefore, in general, one ppm implies one milligram of solute per litre of solution. Percentage (%) A one percent solution is equivalent to 10,000 ppm. Therefore, something that has a concentration of 300 ppm could also be said to have a concentration of (300 ppm)/(10,000 ppm/percent) = 0.03% percent by mass. Mass per Unit Volume (mg/ml or mg/cm3) Some MSDS's (Material Safety Data Sheet) use milligrams per millilitre (mg/ml) or milligrams per cubic centimetre (mg/cm3). Note that 1 ml = 1 cm3 and that cm3 is sometimes denoted as a "cc”. Mass per unit volume is useful when expressing how soluble a material is in water or a particular solvent. For example, "the solubility of substance X is 3 grams per litre". Percent by Mass (% w/w) also called weight percent or percent by weight, this is simply the mass of the solute divided by the total mass of the solution and multiplied by 100%. Normality (N)​ Whilst the unit is archaic in modern chemistry, it is still used in medicine and found in older papers. It is defined as the molar concentration divided by an equivalent factor. It can be expressed as eq/l (equivalent per liter) or meq/l (millieqivalent per litre of 0.001N which can be found in medical reports). It is can either be based on its electron displacement, or on acid/base displacement. For example a solution of HNO3 with a concentration of 1M would have a normality concentration of 1N, as one mole of hydrogen ions is displaced per mole of nitric acid. A solution of barium hydroxide (Ba(OH)2) of concentration 0.5M would have a normality of 1N, as one mole of barium hydroxide displaces two hydroxide ions per mole of barium hydroxide. A solution of Aluminium Chloride (AlCl3) with a concentration of 0.25M would have a normality of 0.75N, due to Aluminium displacing 3 electrons; therefor the normality is 3 times greater than the molarity.