Electrochemical behavior and differential pulse polarographic determination of piperacillin sodium

In an aqueous piperacillin sodium solution, a well-defined single wave or s ingle peak was observed by direct current(DC) polarography or differential pulse polarography(DPP). The peak potential change per pH unit was -54 mV i n the phosphate buffer at 18 degrees C, which indicated that protons were i nvolved in the electrochemical reduction of the 2,3-dioxopiperazine moiety of piperacillin sodium with a H+/e(-) ratio of one. Using a phosphate buffe r of pH 4.3, the 1.0 x 10(-7) M piperacillin sodium single peak could be de termined 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 mon itoring the synthetic process of the antibiotic.