Advancing Pyrethroid Pesticides Analysis: Automation and Green Chemistry in Dispersive Liquid-Liquid Microextraction

Abstract

An automated high-capacity dispersive liquid-liquid microextraction (DLLME) method employing ionic liquids has been developed and optimized for extracting trace levels of five common pyrethroid insecticides - Cyhalothrin, Transfluthrin, Deltamethrin, Ethofenprox and Bifenthrin - from environmental waters, soils and agricultural products. Systematic variation of key parameters including extraction solvent, dispersive solvent and sample pH permitted augmentation of pyrethroid recoveries to between 82.6% and 91.0% across all matrices under investigation. Integration with autosampler technology enabled execution of the rapid, green microextraction technique for over 100 samples daily, constituting a major throughput enhancement over existing methodology. Ensuing extracts were quantified by high performance liquid chromatography coupled to UV detection and automated sample injection, achieving limits of quantification down to sub-ng/L levels, high linearity (R2 ≥ 0.99) from 1-500 ng/L and intra- and inter-day RSDs ≤ 8.3%. By combining automated sample preparation, simplicity of operation and dramatic reductions in organic solvent usage and waste disposal, this novel DLLME-HPLC configuration displays enormous promise as a frontline tool for extensive monitoring of pyrethroid prevalence within complex environmental and food commodities.

Keywords: Dispersive liquid-liquid microextraction, Ionic liquids, Pesticide residues, High-throughput