Preparation of Glassware
Thoroughly clean and rinse all glassware with the supplied BWB Technologies deionized distilled water to ensure that it is clean and free of extractable sodium and potassium.
Glassware should be acid cleaned and rinsed thoroughly in deionized double distilled water prior to use to avoid contamination from extractable metals under test.
Preparation of Solutions
Use analytical grade reagents. Deionized double distilled water is used throughout. Care should be taken during dilution steps as the output of the flame photometer is entirely dependent on the quality of the calibration graph formed by the standards used.
Storage of Prepared Solutions
Store prepared sample solutions and standard solutions in hard polyethylene containers or glass that has been thoroughly cleaned prior to use. Store standard solutions in hard polyethylene containers or in containers of equivalent quality, glassware should be avoided due to some metal ions plating out onto glass surfaces such as Na1+. Keep prepared sample in an airtight container and mix solution thoroughly by repeatedly shaking and inverting container.
Avoid exposing sample to atmosphere as far as possible in order to minimize absorption of atmospheric moisture. Store stock solutions for one month, diluted working concentration solutions should be discarded after 24 hours. Calibration solutions should be prepared fresh immediately prior to use, to ensure accuracy. Use polypropylene pipettes or pipettes having disposable polypropylene tips to measure and transfer solutions. Conduct aspiration of the sample solutions and carry out the measurements following the same procedure as that used for the standard solutions. Prepare standard solutions having a similar matrix as the sample to be analysed.
Preparation of Standard Graph
Set the flame photometer in accordance to MultiPoint/Single Ion Calibration found on page 24 of the BWB Technologies Installation and Operation Manual, to measure potassium emission. Nebulize the lithium working standard solutions and adjust the controls until steady zero and maximum readings are obtained. Nebulize the intermediate working standard solutions and construct a graph relating raw emission data (known as RAW in BWB the flame photometer) to concentration of all the standard solutions.