Trace Analysis of Arsenic by Colorimetry,Atomic Absorption,and Polarography.

摘要

A differential pulse polarographic method was developed for determining total arsenic concentrations in water samples from ash ponds at steam-electric generating plants. After digestion of the sample and isolation of arsenic by solvent extraction,the peak current for arsenic is measured and compared to a standard curve. The effective range of concentrations for this method is from 2to 50 ug/l of arsenic. The precision and accuracy of this polarographic method for determining concentrations of arsenic in water samples were compared to two standard methods,atomic absorption and colorimetry,for observations on replicate analyses of pure standard solutions,split samples from ash ponds,standard reference samples,and standard solutions spiked with potentially interfering elements. The three methods compared favorably for the split samples;however,results of the colormetric method for the replicate analyses were slightly negatively biased.