As, Bi, Se(IV), and Te(IV) determination in acid extracts of raw materials and by-products from coal-fired power plants by hydride generation-atomic fluorescence spectrometry

摘要

Simple and sensitive procedures were developed for the determination of As, Bi, Se and Te in coal, fly ash, and slag samples involving microwave acid extraction and hydride generation atomic fluorescence spectrometry (HG-AFS). Hydrides were generated from hydrochloric acid medium using sodium tetrahydroborate. HG-AFS methods for As, Bi, Se and Te determinations were optimized by using experimental designs. The hydrochloric acid and sodium tetrahydroborate concentrations were in the 2.6-4.8 mol L-1 range and between 0.7-1% for all the metals studied. A microwave acid extraction procedure using aqua regia was used for solid samples treatment. The accuracy was studied using SRM 1632c (coal) and SRM 1633a (coal fly ash) reference materials. Detection limits in the 0.02-1.37 mug g(-1) range were achieved. The methods were applied to several coal, fly ash, and slag samples from a coalfired power plant.