Sensitive and rapid determination of nifedipine using polyvinylpyrrolidone-modified carbon paste electrode

A sensitive, rapid and convenient electrochemical method was developed for the determination of nifedipine based on the greatly-increased oxidation signal on polyvinylpyrrolidone (PVP) surface. In pH 7.5 phosphate buffer, an irreversible oxidation peak at 0.75 V was observed for nifedipine. Compared with the unmodified carbon paste electrode (CPE), the PVP-modified CPE remarkably enhanced the oxidation peak current of nifedipine, showing strong signal enhancement effect. The influence of pH value, amount of PVP, accumulation potential and time on the oxidation peak current of nifedipine was studied. The linear range was from 75 nM to 50 μM, and the detection limit was 20 nM. The proposed method was used to determine the content of nifedipine in tablet samples, and the results consisted with the declared values. Moreover, the recovery tests were performed and the value of recovery was over the range from 97.3 to 102.7%.