Determination of hexavalent chromium and accompanying anions in one run using isocratic ion chromatography with column switching

A method for the simultaneous determination of hexavalent chromium and other inorganic anions like chloride, nitrate and sulfate in aqueous solutions was developed using isocratic ion chromatography with suppressed conductometric detection and column switching. Owing to the large differences in distribution coefficient between chromate and the other species, the chromate is separated from the other anions in a first short column, whereas the other anions are led to a longer second column via a column-switching valve, and separated there. Using standard anion separation conditions the length of the columns and the switching procedure were optimized. The time of analysis for eight anions is less than 12 min and the method can be easily automated. Detection limit and precision are not effected by the switching procedure.