Study On Determination Of Cadmium, Lead, Arsenic In Rice And Gold In Sea Water By Atomic Fluorescence Spectrometry

In this paper, the analytical methods of cadmium, lead, arsenic and gold and the methods of separation and enrichment are summarized. In this study, cadmium and lead in rice was separated and enriched by xanthic ester cotton. Arsenic in the sample solution was also separation and enriched by chromatographic silica gel modified by ammonium pyrrolidine dithiocarbamate. Then, cadmium, lead and arsenic were determinated by hydride generation atomic fluorescence spectrometry. Methyl isobutyl ketone extract Au2HgI4 which is generated by gold with thiourea, Hg and KI under acidic conditions. Then gold in sea water can be determinated indirectly by atomic fluorescence spectrometry.Cadmium and lead in rice samples was adsorpted by xanthic ester cotton after wet digestion. Under the condition of the optimal instrument parameters and experimental conditions, cadmium and lead were measured after eluted by hydrochloric acid. The linear range of Cd and Pb were 0.5 to 20 μg/L and 1 to 20 μg/L, and the linear correlation coefficient were 0.9988 and 0.9967 respectively. The detection limits of Cd and Pb were 0.85 μg/L and 4.5 μg/L respectively, relative standard deviation respectively were 1.5% and 2.3%, and recoveries were 96%～104% and 94%～102%.Rice samples were digested by wet digestion. Arsenic in the sample was separation and enriched by chromatographic silica gel modified by ammonium pyrrolidine dithiocarbamate, and thiourea-ascorbic acid as a reducing agent and a masking agent. The instrument parameters and experimental conditions were optimized. The linear range was 0.1-20 μg/L, and the linear correlation coefficient was 0.9930. The detection limit was 0.050 μg/L and the precision was 1.75%. The recovery rate was between 96% and 106%.The gold in the seawater samples was adsorpted by sponge, and can be form complexes with thiourea. Under acidic conditions, complex can be form a stable compound Au2HgI4 with mercury and KI which can be extracted by methyl isobutyl ketone. The gold in seawater samples was determinated after instrument parameters and test conditions were optimized. The linear range of Au was 0～40 μg/L, and the linear correlation coefficient was 0.9966. The detection limit of this method was 0.0219 μg/L, the relative standard deviation was 1.27% and the recovery was between 98% and 100%.