T/HNAEPI 006-2022 Soil and sediment determination of arsenic, mercury, selenium, antimony, and bismuth using water bath/atomic fluorescence method

Scope

Main technical content: Soil and sediment samples are digested by boiling in aqua regia, and selenium (VI) is reduced to selenium (IV) in hydrochloric acid medium, and bismuth (V) is reduced to bismuth (III). Adding thiourea + ascorbic acid mixed solution, arsenic (V) is reduced to arsenic (III), and antimony (V) is reduced to antimony (III). In the hydride generator, hydrochloric acid solution is used as the carrier gas, and potassium borohydride solution is used as the reducing agent. Arsenic, selenium, antimony, and bismuth are respectively reduced to arsine, selenium hydride, bismuth hydride, and antimony hydride gases. Mercury is reduced to the atomic state and carried into the quartz atomizer by the carrier gas, and then atomized in an argon-hydrogen flame. The ground state atoms are excited by the emission light of the element lamps (arsenic, mercury, selenium, antimony, and bismuth) to produce atomic fluorescence, and the relative intensity of the atomic fluorescence is measured by an atomic fluorescence spectrometer. Within a certain range of element content, the atomic fluorescence intensity is linearly related to the element content in the sample.

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