Determination of trace amounts of molybdate in soil by ion chromatography

Abstract

Trace amounts of molybdate (MoO^2–₄) in soil were determined by single-column ion chromatography (SCIC). The method is based on the chromatographic separation of MoO^2–₄ from other inherent ions (Cl^–, NO^–₃, PO^3–₄ and SO^2–₄) and was characterised in terms of time of analysis, detection limits and column efficiency. Separation of the anions was compared with the use of resin-based and polymethacrylate (PMA) gel analytical columns with 5 mMp-hydroxybenzoic acid (pH 8.25) as the mobile phase. The analytes were quantified by conductimetry with a detection limit of 45 µg l^–1 of MoO^2–₄(signal to noise ratio = 3). The SCIC method for the determination of MoO^2–₄ with the PMA column gave good separation and the results were comparable to those obtained with inductively coupled plasma optical emission spectrometry.