Ionic liquid-based ultrasound-assisted aqueous two-phase extraction of the pyrethroid insecticides in tea drinks

Ionic liquid-based ultrasound-assisted aqueous two-phase extraction was established and applied to the extraction of four pyrethroid insecticides from tea drinks prior to their determination by high-performance liquid chromatography. The main parameters affecting the extraction efficiency, including the type and amount of ionic liquid, type of salt, ultrasonic time, pH value of the sample solution, type of reverse extraction solvent, concentration of (NH4)2SO4 and volume of cyclohexane, were investigated. Under the optimal experimental conditions, good linearity was obtained (r > 0.998). The recoveries of pyrethroids obtained by analyzing the four spiked tea samples were from 70.22 to 122.1%. The intra-day and inter-day precisions were in the range of 2.65–11% and 1.95–10.83% (n = 5), respectively. Limits of detection for determining the analytes were in the range of 4.86–9.53 ng mL−1. The results showed that the present method was a simple, efficient and feasible method for the determination of pyrethroids in the tea drinks.