Switchable hydrophilicity solvent based homogeneous liquid-liquid microextraction for enrichment of pyrethroid insecticides in wolfberry

A simple and sensitive homogeneous liquid-liquid microextraction based on switchable hydrophilicity solvent (SHS-HLLME) has been developed for fast enrichment and determination of pyrethroid insecticides in wolfberry samples via HPLC-UV. In HLLME, N, N-dimethylbenzylamine (DMBA) was used as SHS that can reversibly convert between water-insoluble and water-soluble states by applying CO2 as trigger. Two phase separation was easily achieved by addition of NaOH solution without need of time-consuming of salting-out or forming ionpair, greatly shortening extraction time (3 min). The influencing extraction parameters were investigated and optimized in detail. Under the optimal condition, the method shows good linearity (1.0-200 ng/mL), low limits of detection (0.2-0.5 ng/mL), desirable precision (RSD < 9.8%) and accuracy (RE < 8.7%) and acceptable extraction recovery (71.4%-94.1%). The work provides a novel alternative approach for determination of pyrethroid insecticides at the low nanogram per microliter range with desirable sensitivity.