Natural deep eutectic solvent-decorated magnetic layered double hydroxide as a sorbent for the enrichment of organochlorine pesticides in environmental samples.

A newly designed magnetic layered double hydroxide composite modified with a natural deep eutectic solvent derived from choline chloride and sucrose was synthesized and applied as a sorbent for the enrichment of organochlorine pesticides. The magnetic solid phase extraction (MSPE) procedure was optimized via a small central composite design and response surface methodology. The MSPE method was able to preconcentrate the organochlorine residues in environmental samples prior to GC-MS analysis. Good analytical performance of the proposed method was observed with an enrichment factor of up to 158 and low limits of detection in the ranges of 0.002-0.015 µg·L and 0.03-0.10 ng·g for water and soil, respectively. Satisfactory recoveries for spiked water and soil samples were obtained in the ranges of 80.9-104.7% (RSDs<7.9) and 88.8-104.1% (RSDs<7.3), respectively. This finding highlights the role of natural deep eutectic solvents as modifying agents for magnetic layered double hydroxides, which enhance the efficiency of extraction of the target analytes. The developed MSPE/GC-MS procedure was sensitive and reliable for the determination of trace organochlorine residues in environmental samples.