Indirect atomic absorption spectrometric determination of perchlorate by liquid-liquid extraction in a flow-injection system

Abstract

The determination is based on the continuous liquid-liquid extraction of the copper(I)/6-methylpicolinealdehyde azine/perchlorate ion-pair into 4-methyl-2-pentanone in a flow-injection manifold. The organic fills a loop of an injector situated in an integrated feed system of an atomic absorption spectrometer. Measurement of the copper atomic absorption signal from the organic phase allows the indirect determination of 0.5–5 μg ml −1 perchlorate, giving a 3-fold increase in sensitivity over the conventional spectrophotometric method. The detection limit is 70 ng ml −1. The sampling frequency is 45 ± 5 h −1. The method is highly selective, and has been used for the determination of perchlorate added to serum and urine samples.