在由pH 7.0的磷酸盐缓冲溶液和2.0×10-3mol·L-1对氨基苯磺酸组成的支持电解质中,以100 mV·s-1扫描速率在玻碳电极上先后在电位-1.5~2.5 V范围内循环扫描10周、在电位-1.5~1.5 V范围内循环扫描15 min,制得聚对氨基苯磺酸修饰的玻碳电极。循环伏安法研究发现:对乙酰氨基酚在该修饰电极上出现了一对氧化还原峰,两峰的电位差为30 mV;差分脉冲伏安法研究发现:在pH 5.9的磷酸盐缓冲溶液中,对乙酰氨基酚在0.295 V处出现一良好的氧化峰。且乙酰氨基酚的浓度在2.0×10-7~1.0×10-5mol·L-1范围内与峰电流呈线性关系,检出限(3S/N)为9.0×10-8mol·L-1。据此提出了差分脉冲伏安法测定药片中对乙酰氨基酚的含量,3个样品的测定结果与标示值相符,测得平均回收率为98.6%,相对标准偏差(n=6)均小于3.5%。

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%.