Flow injection spectrophotometric determination of trace amounts of selenium

Abstract

A simple, rapid and sensitive flow injection spectrophotometric method for determination of selenium (0.005–1.5 μg ml −1) is described. The method is based on the catalytic effect of Se(IV) on the reduction reaction of thionine (TN) with sulphide ion, monitored spectrophotometrically at 598 nm. The detection limit is 5 ng ml −1 the relative standard deviation for eight replicate measurements is 1.1% for 1 μg ml −1 of selenium. The sampling rate is 25–30 samples h −1. The procedure was applied successfully to the determination of selenium in real samples.