Application of Two-Step Sequential Liquid-Phase Microextraction in Enrichment and Determination of Pyrethroids in Water and Beverage by Deep Eutectic Solvents

Abstract

DESs (Deep eutectic solvents) were first introduced in 2003 and have been widely used in many fields including extraction an d enrichment , but some of them are too viscous to be applied in enrichment of substance in aqueous phase. So a two-step extraction method could be a possible solution for this. In this study, ceramic-film liquid microextraction technology (CF-LPME) was combined with in-situ IL-LPME(Ionic liquids-liquid phase microextraction), and high-viscosity DESs and IL----[N₄₄₄₄]PF₆ were successfully used to analyze and enrich pyrethroids in environmental water samples and tea beverages, after the single-factor optimization of sample volume and temperature, the three factors with the most significant influence were selected by Plackett-Burman design (P-B design): the addition amount of DESs, the molar ratio of N₄₄₄₄Cl and KPF₆ and the addition amount of N₄₄₄₄Cl, then the three factors was optimized by central composite design (CCD) experiment and optimal value was found by response surface methods (RSM) analysis. Based on the ratio of S/N=3:1, the linear range of The correlation coefficient (R²) ranges from 0.9987 to 0.9997.The LOD values were 1.51 to 2.58 μg/L .The extraction recoveries of 5 μg/L 20 μg/L and 100 μg/L were 90.1%-97.4 %.Therefore, this method is suitable for the determination of pyrethroid pesticides in environmental water samples and juice samples.

Keywords: Two-step sequential liquid-phase microextraction deep eutectic solvents determination