Post-chemiluminescence method of the determination of loperamide hydrochloride in human plasma and pharmaceutical by using dichlorofluorescein as chemiluminescence reagent

A post-chemiluminescence (PCL) was observed when loperamide hydrochloride solution was injected into the reaction mixture after the finish of CL reaction of alkaline N-Chlorosuccinimide (NCS) and dichlorofluorescein. Based on this phenomenon, a simple, sensitive and fast flow injection PCL method was established for the determination of loperamide hydrochloride. The possible mechanism for the PCL reaction was discussed via the investigation of the CL kinetic characteristics, the CL spectra, the fluorescence spectra. The PCL intensity responded linearly to the concentration of loperamide hydrochloride in the range 8.0 x 10(-10) to 6.0 x 10(-7) g . ml(-1) with a linear correlation of 0.9995. The detection limit was 4 x 10(-10) g . ml(-1). The relative standard deviation was 2.4% for 4.0 x 10(-8) g . ml(-1) loperamide hydrochloride (n = 11). This method has been applied to the determination of loperamide hydrochloride in human plasma and pharmaceutical samples with satisfactory results.