Determination of vitamin C in drugs using of an optimized novel TCPO–Amplex red–gold/silver alloy nanoparticles–H2O2 chemiluminescence method by the Box–Behnken design

Response surface methodology (RSM), based on a Box–Behnken design (BBD) was used to optimize three of the most important operating variables (concentrations of TCPO, Amplex red and pH effect) at peroxyoxalate-chemiluminescence (PO-CL) system. For the first time Amplex red (AR) was introduced as a new fluorescent emitter for predicting the reaction mechanism of PO-CL by means of the fluorescence property of its oxidation product. In optimum conditions, it was found that Au/Ag alloy nanoparticles (NPs) could enhance the CL intensity and the method sensitivity toward the evaluation of trace amount of vitamin C. Based on the antioxidant property of vitamin C noticeably the CL signal of the bis-(2,4,6-trichlorophenyl)oxalate–AR–NPs–hydrogen peroxide–sodium salicylate system was quenched in a low basic medium. A simple, rapid and sensitive CL method for the determination of vitamin C has been developed. The results showed a linear relationship between vitamin C concentration and PO-CL intensity in the range of 0.082–82.7 μg/mL. Detection limit of 0.012 μg/mL and the relative standard deviation (RSD)<4% was obtained.