Differential Pulse Voltammetric Determination of Acetaminophen with Poly-p-Aminobenzene Sulfonic Acid Modified Electrode

Poly-p-aminobenzene sulfonic acid modified glassy carbon electrode (GCE) was prepared by cyclic voltammetry (CV) with scanning rate of 100 mV·s-1 in an electrolyte containing PBS of pH 7.0 and 2.0×10-3mol·L-1 p-aminobenzene sulfonic acid solution for 10 cycles first in the potential range of -1.5-2.5 V and then in the potential range of -1.5-1.5 V for 15 min. As shown by the result of CV study on the electrochemical behavior ACOP at the modified electrode, a pair of oxidation and reduction peaks was found giving a potential difference of 30 mV. It was shown by DPV study in PBS of pH 5.9 that a sensitive oxidation peak of ACOP was observed at the potential of 0.295 V (vs.SCE), and linear relationship between values of peak current at this potential and concentration of ACOP was obtained in the range of 2.0×10-7-1.0×10-5mol·L-1, with value of detection limit (3S/N) of 9.0×10-8mol·L-1. Based on these facts, the DPV method was used in the determination of ACOP in its tablets. In analyzing 3 tablet samples of the drug, results in consistency with the labelled value were obtained. Average value of recovery test obtained was 98.6%, with RSD′s (n=6) less than 3.5%.