Determination of Organophosphorus Pesticide Residues in Greek Virgin Olive Oil by Capillary Gas Chromatography

Abstract

In this study, the occurrence of 15 organophosphorus pesticide residues in Greek virgin olive oil was investigated. Analysis was carried out using capillary gas chromatography with specific detectors (FPD and NPD), after sample extraction with n-hexane and cleanup by partitioning between n-hexane and acetonitrile. Sixty-two samples of virgin olive oil were taken from the major production areas and packing companies of Greece during 1992-1994. In 46 samples, 9 organophosphorus pesticides, namely dimethoate, fenthion, omethoate, chlorpyrifos, methamidophos, parathion-methyl, parathion, methidathion, and malathion, were found, in concentrations ranging from 0.0005 to 0.1800 mg/kg. Diazinon, pirimiphos-methyl, paraoxon-methyl, malaoxon, carbophenothion, and azinphos-ethyl were not detected in any sample. In most samples pesticide residues were below the detection limits (0.0001 and 0.001 mg/kg), and most of the positive findings were a fraction (i.e., <0.09-18%) of the FAO/WHO Codex Alimentarius maximum residue limits (MRLs) except for dimethoate, which was ranged between 1 and 45%. Only one sample contained dimethoate residue that exceeded the Codex MRL for refined olive oil.

Determination of residual pesticides in olive oil by GC–MS and HPLC–MS after extraction by size-exclusion chromatography

“…Pesticide use is subject to strict regulations, especially concerning residual levels in commercial foods (olives and olive oil). Several methods [1,2,3,4,5,6,7,8,9,10,11] have been developed for the analysis of pesticide residues in olive oil. These methods generally rely on liquid-liquid or liquid-solid extraction procedures, cleanup on a column and chromatographic separation techniques coupled with mass spectrometric detection, nitrogen-phosphorus detection (NPD) and flame photometric detection (FPD).…”

“…Liquid-liquid pesticide extraction procedures described in the literature are based on partition between the oil and acetonitrile [1,2,3]. Lentza-Rizos and Avramides [1] developed a procedure for extracting pesticides from olive oil by partition between the matrix solubilized in acetonitrile-saturated hexane and solvent extraction with hexanesaturated acetonitrile.…”

“…Lentza-Rizos and Avramides [1] developed a procedure for extracting pesticides from olive oil by partition between the matrix solubilized in acetonitrile-saturated hexane and solvent extraction with hexanesaturated acetonitrile. This method was subsequently used by Hiskia et al [2] to extract organophosphorus pesticides. The same principle of partition between the matrix solubilized in hexane and then partitioned with acetonitrile was adopted by Cabras et al [3] to extract acephate and buprofezin from olive fruit and olive oil.…”

Inmunoensayos rápidos para la determinación de residuos de plaguicidas organofosforados en aceite de oliva

“…Algunos de los plaguicidas utilizados para controlar las plagas pueden persistir hasta la recolección y son lipofílicos, con altos valores de coeficientes de partición n-octanol-agua (k ow ), lo que favorece que sus residuos se concentren en el aceite durante el proceso de extracción, provocando la contaminación del mismo. El uso de plaguicidas puede determinar su presencia en las aceitunas y, consecuentemente, en el aceite de oliva, el cual debe de ser controlado regularmente (202)(203)(204)(205).…”

“…Sin embargo, el modo tradicional lleva a cabo el proceso de extracción y limpieza de forma separada en múltiples etapas, ya que mientras que el método de extracción normalmente depende de la matriz de la muestra, el procedimiento de limpieza podría depender en parte de la naturaleza de las especies interferentes presentes en el extracto. Por este motivo, los métodos de limpieza a bajas temperaturas (210, 226) -basados en la eliminación de las grasas mediante separación por precipitación a baja temperatura-se han aplicado tras la extracción líquido-líquido (75,204,211). Otros métodos propuestos utilizan una combinación de dos o más etapas de limpieza (117,254).…”