Determination of pesticide residues in olives and olive oil by matrix solid-phase dispersion followed by gas chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry.
A novel analytical approach has been developed and evaluated for the quantitative analysis of a selected group of widely used pesticides (dimethoate, simazine, atrazine, diuron, terbuthylazine, methyl-parathion, methyl-pirimiphos, endosulfan I, endosulfan II, endosulfan sulphate, cypermethrin and deltamethrin), which can be found at trace levels in olive oil and olives. The proposed methodology is based on matrix solid-phase dispersion (MSPD), (with a preliminary liquid-liquid extraction in olive oil samples) using aminopropyl as sorbent material with a clean-up performed in the elution step with Florisil, followed by mass spectrometric identification and quantitation of the selected pesticides using both gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode and liquid chromatography tandem mass spectrometry (LC-MS-MS) in positive ionization mode. The recoveries obtained (with mean values between 85 and 115% (obtained at different fortification levels) with RSD values below 10% in most cases, confirm the usefulness of the proposed methodology for the analyses of these kind of complex samples with a high fat content. Moreover, the obtained detection limits, which were below 5 microg kg(-1) by LC-MS analyses and ranged from 10 to 60 microg kg(-1) by GC-MS meet the requirements established by the olive oil pesticide regulatory programs. The method was satisfactorily applied to different olives and olive oil samples.
Ferrer
Carmen
C
Pesticide Residue Research Group, Department of Hydrogeology and Analytical Chemistry, University of Almería, E-04120 La Cañada de San Urbano, Almería, Spain.
Gómez
M Jose
MJ
García-Reyes
Juan F
JF
Ferrer
Imma
I
Thurman
E Michael
EM
Fernández-Alba
Amadeo R
AR
D004117:Dimethoate / Q000032:analysis; D005506:Food Contamination / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D017633:Magnesium Silicates; D031658:Olea / Q000737:chemistry*; D000069463:Olive Oil; D010573:Pesticide Residues / Q000032:analysis* / Q000302:isolation & purification; D010938:Plant Oils / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide
D017633:Magnesium Silicates; D000069463:Olive Oil; D010573:Pesticide Residues; D010938:Plant Oils; C005013:Florisil; D012822:Silicon Dioxide; D004117:Dimethoate