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.

Ultrasound-assisted solid phase extraction of nitro- and chloro-(phenols) using magnetic iron oxide nanoparticles and Aliquat 336 ionic liquid.

A novel and sensitive ultrasound-assisted solid phase extraction (UASPE) method for pre-concentration and determination of ultra-trace amounts of nitrophenols and chlorophenols in water samples was demonstrated. Four hazardous phenolic compounds in water samples were extracted and monitored by high performance liquid chromatography. The results demonstrated that in the presence of Aliquat 336 (ALQ), magnetic iron oxide nanoparticles (MIONPs) were quite efficient in the adsorption and pre-concentration of traces of analytes. MIONPs were synthesized and characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The important parameters influencing the extraction efficiency were studied and optimized. The separation and pre-concentration steps were fast and completed in 10 min. Acetonitrile was used for the desorption of target analytes. Under optimum adsorption conditions, a linear range between 0.015 and 100 µg L(-1) (R(2)≥0.997), and limits of detections (LODs) ranging from 0.005 to 0.041 µg L(-1) were obtained. Enrichment factors in the range of 76-195 were achieved and relative standard deviations (%RSDs) were less than 10.0 (n=3) for the target analytes. The analytical method was successfully applied for environmental water samples such as tap water and river water. The recoveries varied within the range of 70-119% confirming the good performance of the method in various water samples. The results showed that the proposed method is a rapid, convenient and feasible technique for the determination of nitrophenols and chlorophenols in aqueous samples.