Determination of diclofenac sodium by resonance light scattering method using silver nanoparticles as probe

A sensitive, simple and novel method was developed to determine diclofenac sodium (DS) using silver nanoparticles (AgNPs) as probe by resonance light scattering (RLS) technique. It was found that DS could quench the RLS intensity of AgNPs . Moreover, the decrease in RLS intensity was linearly correlated to the concentration of DS over the range of 0.01–2.0   μg   mL −1 . DS can be measured in a short time (5   min) without any complicated or time-consuming sample pretreatment process. Parameters that affect the RLS intensities such as pH, concentration of AgNPs, reaction time, electrolyte concentration , and coexisting substances were systematically investigated and optimized. The results showed that the method had a very good selectivity and could be used conveniently for the determination of DS. The limit of detection (LOD) was 2.85   ng   mL −1 (3σ), and the relative standard deviation (RSD) was less than 3.6% ( n   =   6). Possible mechanism for the RLS changes of AgNPs in the presence of DS was discussed and the method was successfully applied for the analysis of tablets and urine samples.