Determination of some cephalosporins in pharmaceutical formulations by a fluorescence quenching method

A fluorescence quenching method for the determination of some cephalosporins is described, The method is based on the hydrolysis of the cephalosporins in sodium hydroxide to produce the sulfuret, which can quench the fluorescence intensity of fluorescein mercury, Under optimum conditions a linear relationship was obtained between the concentration of cephalosporins and the fluorescence quenching (Delta F) of fluorescein mercury, We have studied four cephalosporins: cefadroxil, cephradine, cefotaximum sodium and cefazolinum. Their detection limits are 5.0 x 10(-6), 1.2 x 10(-6), 1.2 x 10(-5) and 6.0 x 10(-5) mg ml(-1), respectively, The method has been applied to the determination of some cephalosporins in pharmaceutical formulations, The results are satisfactory.