Selective spectrophotometric kinetic determination of cobalt with o-hydroxyphenylthiourea

Abstract

A simple kinetic method has been developed based on the autoxidation of o-hydroxyphenylthiourea to disulphide, which is catalysed by trace amounts of cobalt. The reaction is monitored spectrophotometrically at pH 8.0 and cobalt is determined effectively in the range 5–50 ng ml^–1. This method has been used to determine trace amounts of cobalt present in certain plant materials such as carrot roots and corn grains, in which it plays a vital role in different physiological activities.