Evaluation of QuEChERS Sample Preparation and Gas Chromatography Coupled to Mass Spectrometry for the Determination of Pesticide Residues in Grapes

Abstract

An effective analytical method for pesticides multiresidue determination in grape samples was developed and validated. A modified quick, easy, cheap, effective, robust and safe (QuEChERS) method was used to extract the target compounds. Several sorbent materials were tested for the clean-up step using dispersive solid phase extraction (d-SPE) and Florisil ® was selected. Samples extracts were evaporated before injection in the gas chromatography with mass spectrometry (GC-MS) system in order to improve detectability. Recoveries from blank samples spiked at 0.04, 0.3 and 1.0 mg kg −1 ranged from 95 to 102% with relative standard deviation (RSD) from 1.3 to 19.7%. Method limits of detection (LODm) and quantification (LOQm) ranged from 0.006 to 0.012 and 0.02 to 0.04 mg kg −1 , respectively. The positive matrix effect caused an increase in the peak areas of all compounds and matrix matched calibration curve linearity (coefficient of determination, r 2 ) was higher than 0.98 for all target analytes. The validated method was successfully applied for the determination of 19 pesticides in grape samples.

Pesticide Residues and Effect of Household Processing in Commonly Consumed Vegetables in Jimma Zone, Southwest Ethiopia

“…According to diferent studies, the QuEChERS procedure using the acetate-bufered version presented higher and more consistent recoveries for most compounds including pH-dependent pesticides [22][23][24]. Terefore, to determine the level of pesticides in the vegetables under study, the acetate-bufered QuEChERS sample extraction procedure as used in [22,25] and dispersive solid phase extraction (d-SPE) cleanup technique with anhydrous MgSO 4 and forisil according to [25] was applied in this study with slight modifcations in the amount of the solvent, cleanup, and extraction chemicals used. Generally, the QuEChERS extraction and cleanup method was used in diferent studies to analyze pesticide residues in vegetables with high water content.…”

“…Quality Control. An analytical method that was already validated by diferent scholars [25,26,33] with its efectiveness in determining organochlorine, as well as pyrethroid pesticide residues using GC-ECD for quantifcation, was used in this study. LOD was calculated as three times higher than the level of noise, and the LOQ was equal to ten times the noise level.…”

Fast Sample Preparation Method Using Ultra-High Performance Liquid Chromatography Coupled to Tandem Mass Spectrometry for Natamycin Determination in Wine Samples

“…The use of clean-up becomes an important tool to prolong the equipment useful life, besides reduce the matrix effects when complex matrices, such as wine, are injected. 18 In the last years, dispersive solid phase extraction (d-SPE) have been successfully used as clean-up technique in a large variety of matrices and analytes [19][20][21][22][23] including wine samples. [24][25][26] Besides, performing the extract dilution prior injection into ultrahigh performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) system has proven to be a non-expensive alternative to reduce matrix effect and increase sensitivity.…”