Determination of pesticide residues in almonds by LC-MS/MS and GC-MS: A study of method validation and matrix effects

Abstract

This study was performed to detect pesticide residues in almond. QuEChERS method was validated for determination of 270 pesticides by liquid chromatography-tandem mass spectrometry (LC–MS/MS) and gas chromatography-mass spectrometry (GC–MS). The method had a suitable linearity (R2 ≥ 0.99). Limit of detection (LOD) and limit of quantification (LOQ) were ranged from 0.28 to 3.00 µg kg−1 and 0.92 to 9.98 µg kg−1 respectively. Average recoveries varied from 70.03 % to 119.82 %. Repeatability and intra-laboratory reproducibility of the method, expressed as RSDs were between 1.65–19.15 % and 1.77–19.42 %, respectively. Expanded relative uncertainties ranged from 15.82 % to 46.58 %. Although minimal matrix effects were observed in the LC-MS/MS analysis, a strong matrix effects were detected in the GC–MS analysis. The validated method was used collected for the analysis of collected 90 samples from fifteen different provinces in Turkey. The data showed that all the studied samples did not contain pesticides above the LOD values.

Keywords

• Almond
• QuEChERS
• Matrix effect
• Method validation
• Clean-up