A new chemiluminescence method for determination of dicyandiamide based on the N-bromosuccinimide-merbromin-cetyltrimethylammonium bromide system

A novel and highly sensitive chemiluminescence (CL) method for the determination of dicyandiamide (DCD) has been developed based on the new CL system of N-bromosuccinimide-merbromin-cetyltrimethylammonium bromide in alkaline solution. Experiment conditions were optimized using central composite design-response surface methodology. Under the optimal conditions, the relative CL intensity was linear with the concentration of DCD ranging from 5.0×10^-8 g mL^-1 to 3.0×10^-6 g mL^-1. The detection limit, at the signal-to-noise ratio of 3, was 3.0×10^-9 g mL^-1. The relative standard deviation was 1.9% for 11 repeated determinations of 1.0×10^-6 g mL^-1 DCD. The proposed method was successfully applied to the analyses of DCD in tap water and milk products. And the recoveries were in the range of 87.0-102.3% with relative standard deviation values of 1.2-2.9%. Moreover, the minimum sampling rate was 120 samples h^-1. The possible mechanism of the CL reaction was also discussed.