A fast and sensitive analytical procedure for monitoring of synthetic pyrethroid pesticides' metabolites in environmental water samples

In this paper, we report a simple, fast, and sensitive analytical procedure for monitoring of synthetic pyrethroid pesticides' (SPPs') metabolites in environmental water samples using a novel vortex-assisted salt-induced liquid liquid microextraction (VA-SI-LLME) method coupled with liquid chromatography/tandem mass spectrometric (LC-MS/MS) analysis. VA-SI-LLME was carried out by taking 4 mL of sample solution followed by the addition of isopropanol and ethyl acetate (0.4 mL, 1:2, v/v) as a binary extraction solvent, and 4 g of ammonium sulfate for phase separation. Then, the mixture solution was vortex for 2 min and centrifuged for 3 min to collect the extractant and inject into LC-MS/MS for analysis. Experimental factors affecting the VA-SI-LLME including extraction solvent, extraction solvent volume, salt type, amount of salt, extraction time, and sample pH were completely optimized. The developed analytical method was validated, and the results exhibited good linearity in the concentration ranges between 0.01-100 ng mL(-1) with the correlation coefficient (r(2)) > 0.992 for the target SPPs' metabolites. Excellent limit of quantification and precision were achieved in the range between 0.01-0.1 ng mL(-1), and 1.55-5.06% (in terms relative standard deviation), respectively. The developed method was employed to determine the target SPPs' metabolites in tap, lake, river water, and influent wastewater samples collected in Kaohsiung city area, Taiwan. The extraction recoveries of spiked samples were satisfactory. Therefore, the presented method can be used as a potential alternative analytical procedure for monitoring of pesticides' metabolites in aqueous samples.