Multiresidue Method for Determination of 35 Pesticides in Virgin Olive Oil by Using Liquid−Liquid Extraction Techniques Coupled with Solid-Phase Extraction Clean Up and Gas Chromatography with Nitrogen Phosphorus Detection and Electron Capture Detection

Abstract

A method for the multiresidue determination of 35 pesticides (30 insecticides and five herbicides) in olive oil by gas chromatography (GC) is described. Three liquid-liquid extraction (LLE) procedures based on (i) partition of pesticides between acetonitrile (ACN) and oil solution in n-hexane, (ii) partition of pesticides between saturated ACN with n-hexane and oil solution in n-hexane saturated with ACN, and (iii) partition of pesticides between ACN and oil were tested for the optimization of the highest pesticide recoveries with the lowest oil residue in the final extracts. Experimental tests were preformed in order to study the efficiency of different clean up procedures with N-Alumina, Florisil, C18, and ENVI-Carb solid-phase extraction (SPE) cartridges for the compounds analyzed by GC-nitrogen phosphorus detection. A second step of clean up was also performed for the compounds analyzed by GC-electron capture detection (ECD), by using phenyl-bonded silica (Ph), diol-bonded silica (Diol), cyanopropyl-bonded silica (CN), and amino propyl-bonded silica (NH2) SPE cartridges. LLE of the oil solution in hexane with ACN followed by an ENVI-Carb SPE clean up of the extract gave the best results for all target compounds. The ACN extract was additionally cleaned through a Diol-SPE cartridge for the determination of pesticides analyzed mainly by GC-ECD. Pesticide recoveries form virgin olive oil spiked with 20, 100, and 500 microg/kg concentrations of pesticides ranged from 70.9 to 107.4%. The proposed method featured good sensitivity, pesticide quantification limits were low enough, and the precision, expressed as relative standard deviation, ranged from 2.4 to 12.0%. The proposed method was applied successfully for the residue determination of the selected pesticides in commercial olive oil samples.

Determination of pesticide residues in olives by liquid extraction surface analysis followed by liquid chromatography/tandem mass spectrometry

“…The extraction methods usually applied are matrix solid phase dispersion (MSPD), liquid-liquid extraction using different solvents, gel permeation chromatography (GPC) or solid phase extraction (SPE) (Ferrer, et al, 2005;García-Reyes, et al, 2007a;Guardia Rubio, et al, 2006;Guardia Rubio, et al, 2007c). All of them use different detectors for further analysis, such as flame ionization detector (FID), nitrogen-phosphorus detector (NPD) or electron capture detector (ECD) (Amvrazi and Albanis, 2006), and in the last ten years the use of mass spectrometry (MS) or time of flight mass analyzer (TOF) have become more common (Angioni, et al, 2011;Cervera, et al, 2012;García-Reyes, et al, 2007b;.…”

Determination of some organophosphorus pesticides in water and watermelon samples by microextraction prior to high‐performance liquid chromatography

“…Nowadays, many analytical methods reported in the literature for the determination of these pesticides involve gas chromatography (GC) [4], gas chromatography-mass spectrometry (GC-MS) [5], high-performance liquid chromatography (HPLC) [6], and liquid chromatography-mass spectrometry (LC-MS) [7]. Nevertheless, there are some difficulties for their direct determination due to their low concentration in most cases.…”

Simultaneous determination of organophosphorus pesticides in Chinese herbal medicines by microwave‐assisted extraction coupled with dispersive‐solid phase extraction and gas chromatography

“…The preferred method for the determination of multi-residues is capillary gas chromatography (GC) due to its high separation effi ciency and various selective detectors including fl ame photometric detectors (FPD) (Amvrazi and Albanis, 2006;Fuentes et al, 2008), nitrogen phosphorous detectors (NPD) (Yage et al, 2005;Díaz-Plaza et al, 2007) and electron capture detectors (ECD) (Ho and Hsieh, 2001;Chen et al, 2002). In order to eliminate interferences and keep the chromatographic system in good working order, an eff ective extraction and clean-up process is mandatory.…”