Deep eutectic solvent-modified mixed iron hydroxide-silica: Application in magnetic solid-phase extraction for enrichment of organochlorine pesticides prior to GC-MS analysis.

Abstract

A new type of magnetic material based on silica-coated mixed iron hydroxides functionalized with deep eutectic solvent was utilized for the magnetic solid-phase extraction of organochlorine pesticides prior to gas chromatography-mass spectrometry analysis. Choline chloride and phenol were selected as the hydrogen bond acceptor and donor, respectively, for preparing the deep eutectic solvent-modified magnetic surface. The modified surface possessed superior enrichment capability for organochlorine pesticides. Under optimal extraction conditions, viz., 10mg sorbent, 5mL sample solution, and 200 μL acetone (desorption solvent), linearity was obtained in the range 0.005-200μg/L, with coefficients of determination greater than 0.997. The limits of detection and quantification were as low as 0.6-10and 5-60ng/L, respectively, whereas the enrichment factors were in the range of 31-100. The precisions evaluated in terms of the relative standard deviations of the intra- and inter-day experiments were <4.9 and 7.6%, respectively. The developed method was successfully applied for determining the organochlorine residues in agricultural products. Satisfactory recoveries in the range of 71.2-110.3% were obtained, with a relative standard deviation of <8.0%. The proposed material is a promising sorbent for the preconcentration of organochlorine residues.