Electrochemical behavior and differential pulse polarographic determination of piperacillin sodium

In an aqueous piperacillin sodium solution, a well-defined single wave or single peak was observed by direct current (DC) polarography or differential pulse polarography (DPP). The peak potential change per pH unit was -54 mV in the phosphate buffer at 18 degrees C, which indicated that protons were involved in the electrochemical reduction of the 2,3-dioxopiperazine moiety of piperacillin sodium with a H+/e- ratio of one. Using a phosphate buffer of pH 4.3, the 1.0 x 10(-7) M piperacillin sodium single peak could be determined by DPP with relative standard deviation of 1.6% (n=3). Piperacillin sodium could be analyzed without interference from penicillin G-potassium, which enabled the employment of DPP as a fast and simple technique for monitoring the synthetic process of the antibiotic.