Silver nanoparticle enhanced chemiluminescence method for the determination of nitrazepam

We report on a simple and sensitive chemiluminescence (CL) method to determine nitrazepam. This method is based on the fact that rhodamine 6G (Rh6G) enhanced the weak CL emission of the reaction of hexacyanoferrate with nitrazepam, and that it was further enhanced by silver nanoparticles (AgNPs). The effects of the concentrations of K3Fe(CN)6, Rh6G, AgNPs and NaOH on the CL reaction were investigated. Under the optimum conditions, the CL intensity was proportional to the concentration of nitrazepam in the range from 1.0 nM to 10.0 μM. The detection limit (3σ) was at 0.1 nM. The relative standard deviation was 2.1% (at a 0.1 μM concentration and for n = 11). The method was successfully applied to the determination of nitrazepam in Coca-Cola beverage, urine and plasma, and the recovery was 98 - 103%. We also considered the possible CL reaction mechanism.