Spectrophotometric determination of cephalosporins with leuco crystal violet

A simple and sensitive spectrophotometric method for,the determination of cefotaxime, ceftriaxone and cefradine with leuco crystal violet is presented. The determination is based on the reduction of potassium iodate in acidic medium, followed by hydrolysis of beta-lactam ring of cephalosporins with sodium hydroxide. The formed iodine reacts with leuco crystal violet. The crystal violet dye of maximum absorption at 588 nm is formed. Its absorbance was measured within pH range of 4.0-4.2 in 1 cm cuvettes. Beer's law was obeyed in the concentration range: 0.8-4.8 mug mL(-1), 0.4-1.6 mug mL(-1) and 0.2-2.0 mug mL(-1) for cefotaxime, ceftaxone and cefradine, respectively. The molar absorptivity of the coloured compound is 8.4 x 10(4) L mol(-1) cm(-1) for cefotaxime, 2.4 x 10(5) L mol(-1) cm(-1) for ceftriaxone and 1.6 x 10(5) L mol(-1) cm(-1) for cefradine. The analytical parameters were optimized and the method was successfully applied to the determination of cefotaxime, ceftriaxone and cefradine in pharmaceuticals.