Advancing pyrethroid pesticides analysis: Semi-automation and green chemistry in dispersive liquid-liquid microextraction

A semi-automated dispersive liquid-liquid microextraction (DLLME) method with in situ generated ionic liquids for the trace analysis of five pyrethroids (cyhalothrin, transfluthrin, deltamethrin, ethofenprox, and bifenthrin) from environmental water, soil, and agricultural products was developed. Newer and safer solvents were used to reduce variability, and key parameters such as sample pH and extraction solvents were systematically optimized, resulting in substantial improvements in pyrethroid recoveries across all matrices. An autosampler was integrated to process more than 100 samples per day, exceeding conventional methods. The method was coupled with HPLC-UV detection and an automated injection system, and limits of quantitation in the sub-ng/L range were achieved, with high linearity (R2 >= 0.99 over 1-500 ng/L) and excellent precision (RSDs <= 8.3 %). This environmentally friendly DLLME-HPLC platform reduces the organic solvent usage and waste generation for pyrethroid monitoring in complex matrices.