Survey of organophosphorus pesticide residues in virgin olive oils produced in Chile

Abstract

Dimethoate, diazinon, parathion methyl, pirimiphos methyl, malathion, fenthion, chlorpyriphos, methidathion and azinphos methyl were determined in 71 olive oil samples produced in Chile from different varieties of olives (arbequina, frantoio, picual, lechino and blend) at three different harvest periods (2007, 2008 and 2009). The target pesticides were determined using a validated analytical method based on microwave-assisted liquid–liquid and solid-phase extraction with subsequent GC–FPD detection and GC–MS/MS for confirmation purposes. In 79% of the samples, five of the nine pesticides tested were detected with a frequency of one pesticide per sample. The highest detection rates were observed for the residues of chlorpyriphos and diazinon. The average concentration of chlorpyriphos, diazinon, azinphos methyl and methidathion were 0.084, 0.057, 0.024 and 0.010 µg g⁻¹, respectively. Higher contents of organophosphorus pesticides (OPPs) were found in regions where intensive agriculture is practiced. However, the levels of OPPs were reassuringly low and indicate that olive oil produced and exported from Chile does not currently represent any risk for consumers.

Keywords:

• organophosphorus pesticides
• olive oil
• monitoring
• microwave-assisted extraction
• gas chromatography

Acknowledgements

The authors thank FONDECYT for financial support through Project 11060461. Thanks are also due to Betsabé Sepúlveda from CEPEDEQ (Centro para el Desarrollo de la Química, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile) for her contribution in the collection of samples from producers in different Regions of Chile.