Flow injection chemiluminescence method for determination of nifedipine based on persulfate-luminol reaction

A novel chemiluminescence (CL) system coupled with flow injection technique was developed for determination of nifedipine. It was found that the luminol could react with persulfate in sodium hydroxide media, producing a weak chemiluminescence, which could be sensitized intensively by nifedipine. The sensitized chemiluminescence intensity was a linear function of nifedipine concentration. Under the optimal conditions (luminol concentration: 1.0 x 10(-4) mol/L, persulfate concentration: 1.0 x 10(-3) mol/L, sodium hydroxide concentration: 0.2 mol/L), the proposed method had a linear range of 0.05 similar to 5.0 mg/L with a regression equation DeltaI = 330.2C + 52.83 (C: nifedipine concentration, mg/L, r = 0.9991). The detection limit was 0.017 mg/L with a RSD of 2.8% (nifedipine concentration: 0.5 mg/L, n = 11). This method was sensitive, simple, rapid, and was successfully applied to the determination of nifedipine in tablets.