Determination of selenate by single-column ion chromatography.

Chromatographic parameters were optimized to determine selenate (SeO4(2-)) by single-column ion chromatography with the simultaneous detection of Cl-, NO2-, NO3- and SO4(2-). Separation was conducted on a low-capacity anion-exchange column, and anions were quantified by conductimetric detection. The eluent stream consisted of 4 mM phthalic acid adjusted to pH 4.6 with sodium borate. Accurate measurement of trace amounts of SeO4(2-) was evident in the presence of high background levels of other ions including Cl-, NO-3 and up to 40 mg l-1 SO4(2-). Resolution of SeO4(2-) and SO2-4 was demonstrated up to 80 mg l-1 SO4(2-). The detection limit of SeO4(2-) was 18 micrograms l-1 with a relative standard deviation of 1.46%.