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Development of an analytical method for the determination of pesticides in tropical fruits based on combination of QuEChERS extraction and dispersive liquid-liquid microextraction by LC-QTOF-MS/MS
  • Sabriye Sel,
  • Elif Öztürk Er,
  • İkbal Koyuncu
Sabriye Sel
Yildiz Technical University
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Elif Öztürk Er
Istanbul Technical University
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İkbal Koyuncu
Yildiz Technical University

Corresponding Author:[email protected]

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Rationale: Pesticides are poisonous substances or mixtures of dangerous chemicals used to prevent, dissuade, control, or eradicate insects, weeds, rodents, fungi, or other potentially dangerous organisms. Pesticides must be separated from complex matrices before analysis by performing the proper extraction, cleaning, and/or preconcentration processes. The QuEChERS method served as a matrix clean-up tool and the DLLME method preconcentrated the analytes for their determination at trace levels. To increase the detection efficiency, a simple and efficient pretreatment process is required. Method: In this study, QuEChERS extraction was combined with dispersive liquid-liquid microextraction (DLLME) to extract pesticides from tropical fruits for determination by a highly accurate and sensitive liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS/MS) system. All the variable parameters of the DLLME method were optimized to improve the extraction output for all analytes and the limits of detection and quantitation (LOD and LOQ) values, which are quite satisfactory, were calculated under the optimum conditions. Results: The LOD and LOQ values were found in the range of 0.004 – 0.013 and 0.27 – 0.61 µg/L, respectively. The detection limits achieved by direct LC-QTOF-MS/MS analysis were increased by about 10 – 260 fold using the optimized DLLME method. To assess the accuracy and applicability of the developed method, recovery experiments on tropical fruits were carried out. The matrix-matched calibration method was used to enhance the quantification accuracy of the analytes in kiwi, pineapple, and mango matrices, with percent recoveries ranging between 89 and 117%. Conclusion: The results show that the proposed method is feasible for the determination of pesticides with high accuracy and precision. The above approach acts as a reference method for monitoring tropical fruits while proposing prospective solutions for pesticides assessment in more complex matrices.