TRACE ANALYSIS OF ULTRAPURE ARSENIC AND SELENIUM BY GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROMETRY

A method for the determination of trace and ultratrace impurities like Co, Cu, Cr, Fe and Ni in pure arsenic and selenium by graphite furnace atomic absorption spectrometry has been developed. The sample preparation and the measurement was performed in a clean laboratory with HEPA filtrated air providing a class 100 working environment. For correction on the blank the expected values estimated from a set of blanks were used respecting the distribution (normal or lognormal) tested by Shapiro-Wilk test. Detection limits for the whole procedure estimated according to the IUPAC 3 sigma definition are somewhat higher for the Se matrix, but still allow the analysis of As and Se samples of 5N5 purity as required.