Chemiluminescence determination of tetracyclines based on their reaction with hydrogen peroxide catalysed by the copper ion

Abstract

A flow injection-based method for the determination of tetracycline, chlortetracycline and oxytetracycline has been proposed. It is based on the reaction of the tetracyclines with hydrogen peroxide, catalysed by the copper ion in ammonia medium. Persulfate was used as a co-oxidizing agent. The procedure allows the determination of 0.025–2.5 nmol of chlortetracycline and 0.25–25 nmol of tetracycline and oxytetracycline (50 µl per injection) by the flow-injection method compared with 0.005–50 µmol l^–1 of chlortetracycline and 0.05–500 µmol l^–1 of tetracycline and oxytetracycline by the classical batch method. The method is sensitive, selective and easy to operate and can be used for the determination of tetracyclines in pharmaceutical preparations. A discussion on the possible reaction mechanism is presented.