Multi-Residue Analysis of Pesticides in Pistachio Using Gas Chromatography-Mass Spectrometry (GC/MS)

Background: Analysis of pesticide residues in food and other environmental commodities have become an essential requirement for consumers, producers, food inspectors and authorities. This study is focused on validation of an accurate, rapid and reliable method for multi-residual analysis of pesticides in pistachio as a strategic crop for export and one of the main nuts in Iranian food basket. Methods: We developed a "Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method based on spiking blank samples and used the data for drawing calibration curves instead of standard solutions. Sample preparations were developed for determination of 12 pesticide residues in pistachio by gas chromatography-mass spectrometry (GC/MS). Results: Recovery of pesticides at 5 concentration levels (n=3) was in the range of 81.40% - 93.08 %. The method proved to be repeatable in the majority of samples with relative standard deviation (RSD) of lower than 20%. The limits of detection and quantification for all pesticides were 2 ppb and 10 ppb, respectively. Conclusion: The calibration curves of pesticides were linear in the range of 10-500 (ng/g) and correlation coefficient of entire pesticides was higher than 0.994. The recovery of pesticides at 5 concentration levels (n=3) was in range of 81.41- 91.80 %. The method was proved to be repeatable with the majority of RSDs being lower than 20%. The limits of detection and quantification for all pesticides were 2 and 10 ppb, respectively. The recoveries and repeatabilities were in accordance with the criteria set by SANCO Guideline (Commission of the European Communities, 2006).