Chemiluminescence determination of tetracycline and oxytetracycline in pharmaceutical preparations using Ru (bipy)3 2+-cerium (IV) system

A new chemiluminescence (CL) method for the determination of tetracycline and oxytetracycline is developed, based on the CL reaction of tetracycline and oxytetracycline with Ru (bipy)3 2+ and Ce (IV). In sulfuric acid medium, the CL emission is generated upon continuous oxidtion of Ru(bipy)3 2+ by cerium (IV). The emission intensity is greatly enhanced when tetracycline and oxytetracycline are introduced into the reaction system after acid degradation. Under the optimum conditions, the calibration curves are linear over the range of 8.0×10−8∼4.0×10−6 mol/L for tetracycline and of 2.0×10−7∼4.0×10−5 mol/L for oxytetracycline, with the detection limits are 4.2×10−8 mol/L for tetracycline and 1.5×10−7 mol/L for oxytetracycline, respectively. The proposed method was used for the determination of tetracycline and oxytetracycline in pharmaceutical formulations with good results.