Determination of arsenate, germanate, phosphate and silicate by ion chromatography using a post-column reaction (molybdenum blue) detector

A selective post-column detection system was developed for the determination of As(V), Ge(IV), P(V) and Si(IV) oxoanions after separation by ion chromatography. Detection is based on the molybdenum blue reaction which, by careful choice of reaction conditions, will react with all four oxoanions with good sensitivity. Quantitative studies revealed slightly curved, though acceptable, calibration functions, with detection limits ranging from 0.06 to 2.0 mg l-1.