Automated one-step supercritical fluid extraction and clean-up system for the analysis of pesticide residues in fatty matrices

Abstract

An automated supercritical fluid extraction and in-line clean-up system has been developed for organochlorine and organophosphate pesticide residues contained in fats. This procedure utilizes supercritical carbon dioxide modified with 3% acetonitrile at 27.58 MPa and 60°C to extract and separate the pesticide residues from the fat on a C 1 bonded phase preparative column at 95°C. The automated C 1 system recovers 86 of 117 nonpolar to moderately polar organochlorine and organophosphate pesticides from fats. Ten of the 31 pesticides not recovered through the system are not recovered through the conventional clean-up sorbent, Florisil. Pesticide residues can be separated from 0.68 g of butter fat and 0.67 g corn oil, resulting in 2.9 mg of butterfat and 2.1 mg corn oil residue co-eluting into the pesticide fraction. Also, this integrated method can extract and clean-up a 5 g sample of fatty foods containing <18% fat and 70% moisture. The automated C 1 system is reproducible and the amount of co-extracted sample residue in the pesticide fraction yields results comparable to the current methodology, which uses organic solvent extraction and gel permeation chromatography, along with a final Florisil column clean-up step. This automated C 1 system simplifies the extraction and clean-up step while reducing solvent usage and hazardous waste.