STP116

    Control of Interferences Caused by Acids and Salts in the Flame Photometric Determination of Sodium and Potassium

    Published: Jan 1952


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    Abstract

    In the determination of sodium and potassium by flame photometry, substantial negative errors are produced by moderate concentrations of common acids and salts in the test solution when the instrument operates on a mist produced in a spray chamber and is used without an internal standard. Our work indicates that these errors are primarily caused by the decrease in the amount of evaporation that occurs between the time the mist droplets form and enter the flame. It appears that the presence of acids or salts in the mist droplets hinders evaporation of the droplets and that the resulting increased amount of water carried into the flame results in a lowered radiation intensity produced in the flame by the test element. Interference from this source can be virtually eliminated by adding a high concentration of a salt or acid, as a buffer, to both the test solution and comparison standards. Lithium chloride is an exceptionally good buffer because, in addition to eliminating errors produced by acids and salts, it serves also as a radiation buffer to reduce interference by mutual excitation.


    Author Information:

    Eggertsen, FT
    Shell Development Co., Emeryville, Calif.

    Wyld, G
    Shell Development Co., Emeryville, Calif.

    Lykken, L
    Shell Development Co., Emeryville, Calif.


    Paper ID: STP39246S

    Committee/Subcommittee: D02.08

    DOI: 10.1520/STP39246S


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