Simultaneous Determination of Phosphate, Silicate,and Arsenate by On-line Column Flow Injection Analysis

The simultaneous determination of phosphate, silicate and arsenate has been examined by adapting an anion-exchange column to the flow injection analyzer. Determination is based on the absorption at 810 nm of the heteropoly blue formed with ascorbic acid as reducing agent. Detection limits(S/N = 3) are 3.1 ng, 0.55 ng and 3.0 ng for phosphorus, silicon and arsenic, respectively.