STP573: Interlaboratory Study of the Cold Vapor Technique for Total Mercury in Water

    Winter, JA
    Method Development and Quality Assurance Research Laboratory, U.S. Environmental Protection Agency, National Environmental Research Center, Cincinnati, Ohio

    Clements, HA
    Method Development and Quality Assurance Research Laboratory, U.S. Environmental Protection Agency, National Environmental Research Center, Cincinnati, Ohio

    Pages: 15    Published: Jan 1975


    Abstract

    The American Society for Testing and Materials (ASTM) and the U.S. Environmental Protection Agency (EPA) conducted a joint study of the cold vapor technique for total mercury in water, before formal acceptance of the method by each organization. The method employs an acid-permanganate-persulfate oxidation step with heat.

    Following Youden's design, samples were prepared in pairs as similar yet different concentrates in sealed glass ampuls. Analysts added an aliquot of each to distilled water and to a natural water of choice. Single analyses were made on each sample and recoveries compared. Results from 90 analysts showed a positive bias of 53 to 99 percent and a relative deviation of 67 to 79 percent at the minimum detectable level of 0.2 µg/liter. At the 0.5 µg/liter level, the bias was still positive but reduced to 18 to 32 percent whereas the relative deviation held at 55 to 80 percent. At the 3 to 10 µg/liter level, the bias was small (-7 to +4 percent) and the relative deviation was reduced to a 30 to 40 percent level. Natural waters exerted little effect on the precision or accuracy of the method.

    Keywords:

    water quality, mercury (metal), environmental testing, statistical analysis, water pollution


    Paper ID: STP39037S

    Committee/Subcommittee: D19.95

    DOI: 10.1520/STP39037S


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