Fast and easy multiresidue method employing acetonitrile extraction/partitioning and "dispersive solid-phase extraction" for the determination of pesticide residues in produce.
A simple, fast, and inexpensive method for the determination of pesticide residues in fruits and vegetables is introduced. The procedure involves initial single-phase extraction of 10 g sample with 10 mL acetonitrile, followed by liquid-liquid partitioning formed by addition of 4 g anhydrous MgSO4 plus 1 g NaCl. Removal of residual water and cleanup are performed simultaneously by using a rapid procedure called dispersive solid-phase extraction (dispersive-SPE), in which 150 mg anhydrous MgSO4 and 25 mg primary secondary amine (PSA) sorbent are simply mixed with 1 mL acetonitrile extract. The dispersive-SPE with PSA effectively removes many polar matrix components, such as organic acids, certain polar pigments, and sugars, to some extent from the food extracts. Gas chromatography/mass spectrometry (GC/MS) is then used for quantitative and confirmatory analysis of GC-amenable pesticides. Recoveries between 85 and 101% (mostly > 95%) and repeatabilities typically < 5% have been achieved for a wide range of fortified pesticides, including very polar and basic compounds such as methamidophos, acephate, omethoate, imazalil, and thiabendazole. Using this method, a single chemist can prepare a batch of 6 previously chopped samples in < 30 min with approximately 1 dollar (U.S.) of materials per sample.
Anastassiades
Michelangelo
M
U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 E. Mermaid Ln, Wyndmoor, PA 19038, USA.
Lehotay
Steven J
SJ
Stajnbaher
Darinka
D
Schenck
Frank J
FJ
D000097:Acetonitriles / Q000737:chemistry*; D002138:Calibration; D005638:Fruit / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D009426:Netherlands; D010573:Pesticide Residues / Q000032:analysis*; D015203:Reproducibility of Results; D012997:Solvents; D014675:Vegetables / Q000737:chemistry*
D000097:Acetonitriles; D007202:Indicators and Reagents; D010573:Pesticide Residues; D012997:Solvents