DETERMINATION OF ARSENIC AND SULFUR SPECIES IN ENVIRONMENTAL-SAMPLES BY ION CHROMATOGRAPHY

An eluent, 3.5 mM Na2CO3-2.6 mM NaOH, has been developed for anion chromatography. It was found to be better suited to anion determination in environmental samples than a HCO3--CO32- eluent. This eluent was effective in the determination of AsO43- concentrations down to 0.3 µM and of some As(III) species analyzed as ASO43- following oxidation. Total As levels in smelter flue dust samples determined by this method agree with those determined by X-ray methods. Oxidation of SO32- to SO42- by O2 in the eluent stream complicates the determination of SO32- and probably makes this method unreliable for the direct determination of SO32-in complex mixtures. Fe(III) present in SO32- solutions catalyzed the oxidation to SO42-. The addition of Cu(II) also increased the rate of oxidation of SO32-, not only of the sample to which it was added, but also of subsequent samples containing no Cu(II). © 1979, American Chemical Society. All rights reserved.