Flow injection chemiluminescence method for the determination of pentoxyverine citrate based on NCS-dichlorofluorescein post-chemiluminescence reaction

A post-chemiluminescence (PCL) phenomenon was observed when pentoxyverine citrate solution was injected into the reaction mixture after the finish of chemiluminescence (CL) reaction of N-chlorosuccinimide (NCS) and alkaline dichlorofluorescein. The possible reaction mechanism was proposed based on the studies of the CL kinetic characteristics, the CL spectra and the fluorescence spectra of some related substances. Based on the PCL reaction, a rapid and sensitive method for the determination of pentoxyverine citrate was established. The linear response range of this method was from 6.0 × 10−9 to 1.0 × 10−6 g mL−1 with a linear correlation coefficient of 0.9998. The relative standard deviation for 2.0 × 10−8 g mL−1 pentoxyverine citrate was 2.1% (n = 11). The detection limit was 9 × 10−10 g mL−1. This method has been applied to the determination of pentoxyverine citrate in human plasma and pharmaceutical samples with the satisfactory results.