Rapid Determination of Total Mercury in Enviromental Samples by the DMA-80 Direct Mercury Analyzer

DMA-80 direct mercury analyzer was applied to rapid determination of total mercury in 8 kinds of samples, including soil, rice, human hair, gabbage, waste water and etc. An appropriate amount of solid or liquid sample was placed in the nickel or quartz sample boat, dried at 150 ℃-300 ℃ for 30-300 s, selected according to different properties of the sample; mercury in the sample was oxidized to HgO at 800 ℃-950 ℃ for 180 to 420 s. The HgO was reduced to Hg0 vapor in the catalytic reductor, and the Hg0 vapor was amalgamated and trapped selectively in the amalgamator, and after desorption pure mercury vapor was carried over to the optical cell for AAS determination at the wavelength of 253.7 nm. Standard curve was used for quantification. Two standard samples (GSS-3 and GSD-9) was analyzed by the analyzer under the optimized conditions, giving values of ∑Hg contents in consistency with the certified values, with values of RSD′s (n=5) of 3.2% and 5.4% respectively. Contents of total mercury in samples of sludge, soil, gabbage extracts, domestic sewage, and river water were also determined by the analyzer, giving results checked quite well with those obtained by conventional AFS.