Resonance Rayleigh scattering method for determination of ethion using silver nanoparticles as probe.

A simple, novel and sensitive method was developed to determine ethion insecticide in water samples. This method was based on the interaction of ethion with silver nanoparticles (AgNPs) and quenching of the resonance Rayleigh scattering (RRS) intensity. The change in RRS intensity (ΔIRRS) was linearly correlated to the concentration of ethion over the range of 10.0-900.0 µg L(-1). Ethion can be measured in a short time (3 min) without any complicated or time-consuming sample pretreatment process. Parameters that affect the RRS intensities such as pH, concentration of AgNPs, standing time, electrolyte concentration, and coexisting substances were systematically investigated and optimized. Interference tests showed that the developed method has a very good selectivity and could be used conveniently for determination of ethion. The limit of detection (LOD) and limit of quantification (LOQ) were 3.7 and 11.0 µg L(-1), respectively. Relative standard deviations (RSD) for 15.0 and 60.0 µg L(-1) of ethion were 4.1 and 0.2, respectively. Possible mechanisms for the quenching of RRS of AgNPs were discussed and the method was successfully applied for the analysis of spiked real water samples.