Study On Determination Of Microelement And Trace Element In The Antimony Conce-Ntrate And Barite By Atomic Spectrometry

On the basis of a review of the current situation and progress indetermination As, Hg, Bi, Se, Sn, Pb and Cd methods at home and abroad,determination of harmful element by atomic spectrum was studied, atomicspectrometry analysis that is simple, fast and has low detection limit needs to besuitable to the request of commodity inspection.1) A method for the determination of trace arsenic and mercury in antimonyconcentrates by hydride generation atomic fluorescence spectrometry(HG-AFS)was investigated. The method of dissolving sample and the effect ofconcomitant ion were studied. It was found that aqua regia can be used todissolve the sample completely, with maximum quantities of dissolved arsenicand mercury. The interference of chemical elements in antimony concentrateswas avoided by adding thiourea-Vc. The matrix of antimony was vaporized withtartaric acid during sample pre-treatment. Trace arsenic and mercury weredetermined in real samples. The detection limits of 0.45 ng·mL^-1 and 0.02ng·mL^-1 were obtained, the relative standard deviations (RSD% n=11) are 1.2%and 2.4%, and the recoveries are 96.3%～102% and 97.5%～103% for As andHg respectively. This method has proved rapid, accurate and highly sensitive.2) The interference of Sb(Ⅴ) in determination of Se and Bi in antimonypowder and antimony compound has been studied in different acidity, It is foundthat the interference of antimony has been reduced apparently in high acidity. Meanwhile, according to the difference of hydride generation reaction betweenSb(Ⅴ) and Sb(Ⅲ), a sensitive and rapid method has been developed and used todetermine Se and Bi in real samples. The detection limits of 0.35 ng·mL^-1 and0.50 ng·mL^-1 were obtained, the relative standard deviations (RSD% n=11) are2.4% and 1.7%, and the recoveries are 97.5%～103% and 92.0%～96.0% for Seand Bi.3) A method for determination of trace Sn by HG-AFS was described. Theinfluence of HG-AFS operation conditions, various acidic media andconcentration of solution was studied. Experimental conditions were discussedand the influence of coexisting elements were investigated. The detection limitsof 0.50 ng·mL^-1 was obtained, the relative standard deviations (RSD% n=11) are0.83%～7.2%, and the recoveries are 91.0%～96.6% for Sn respectively.4) A method of microwave acid extraction Pb and Cd in barite for thedetermination by AAS was developed. As a result of the investigation, PTFEpressure vessel and common pressure acid extraction methods spend and werelonger than this method. Extraction rate and precision of this method was betterthan others, the relative standard deviations are 1.3%～3.2% and 1.3%～3.2%,and the recoveries are 95.1%～99.5% and 97.1%～104% for Pb and Cd.