Analysis of pesticide residues by on‐line reversed‐phase liquid chromatography–gas chromatography in the oil from olives grown in an experimental plot

Abstract

This paper describes the use of a fully automated on-line reversed-phase liquid chromatography-gas chromatography (RPLC-GC) method for the determination of four organophosphorus pesticides (dimethoate, methidathion, chlorpyriphos and fenitrothion) in olive oil. These pesticides are among those more extensively used to control pests and disease in olive trees. Various treatments with these pesticides, at various doses and stages of olive ripening, were carried out in an olive grove. The olives were harvested in mid-December and immediately processed into oil in the laboratory. Fully automated analyses by on-line RPLC-GC using the through oven transfer adsorption desorption (TOTAD) interface was carried out without any kind of sample pretreatment other than a simple filtration step. A statistical analysis was performed. No dimethoate remained in the oil owing to the high solubility of dimethoate in water. Differences between the other three pesticide residues were significant. Chlorpyriphos provided the lowest residues, followed by fenitrothion and methidathion.

Comparing the benefits between pesticides and ethylene treatments in reducing olive moth population numbers and damage

“…This pesticide remains in the olive fruits even after 8 months of storage (Cabras et al 1997). Nevertheless, Sanchez et al (2006) have demonstrated that, in olive oil, no dimethoate remained owing to the high water solubility of this chemical, because olive oil is obtained after fruit-pressing and elimination of the water phase from the extract. Regarding natural enemies of P. oleae, dimethoate is found to be moderately harmful to Trichogramma cacoeciae at field-recommended doses (Youssef et al 2004).…”

On‐line solid‐phase extraction for liquid chromatography–mass spectrometry analysis of pesticides

“… reported an on‐line coupled RP‐LC–GC method for organophosphorus, organochlorine and triazine pesticides using the through oven transfer adsorption desorption interface with subsequent simultaneous electron‐capture and nitrogen–phosphorus detection by a postcolumn splitter. The use of fully automated on‐line RP‐LC–GC has also been reported for the determination of four organophosphorus pesticides (dimethoate, methidathion, chlorpyriphos, and fenitrothion) in olive oil . However, the majority of reports on the application of on‐line SPE describe pesticides monitoring in aqueous environmental samples with only a few that have been applied to food analysis.…”

Sorptive extraction techniques in sample preparation for organophosphorus pesticides in complex matrices

“…SPE is currently one of the most widespread extraction methods for the pretreatment of environmental [16][17][18][19][20][21], food [22,23] and biological samples [24,25]. The basic principle of SPE is the transfer of analytes from an aqueous phase to the absorption sites of the adjacent solid phase.…”