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ملخص البحث |
Abstract
This study presents the application and testing the efficacy of QuChERs for extraction of chlorpyrifos (CF) from tomato. Extraction procedure follows AOAC 2007.01 official method. For analysis a HPLC coupled with fluorescence detector was verified according to SANTE/2020 guidance on pesticide analytical methods in terms of linearity, range, recovery, and precision.
The chromatographic conditions were C18-column as stationary phase, and a mixture of methanol: water (95:5 v/v) as mobile phase in isocratic elution pattern and a flow rate of 0.8 mL/min. The fluorescence detection parameters were ? excitation: 280 nm, and ? emission: 340 nm.
A matrix matched calibration curve was Y= (724169+2.3%) X + (459043+10.8%), R2 = 0.996+0.26% (n =3), where Y: Peak area, and X: Concentration (µg/g). Range was 0.05 -10.0 (µg/g). Percent recovery ranged from 77.5 to 109.4%, and percent relative standard deviation for intra- and inter-day precision was less than 20%. Hence, it was suitable for determination of CF in tomato.
CF was detected in three tomato samples (Total samples: 7) at a concentration of 1.25 to 5.51 (µg/g), which was above the maximum residue limit (MRL). Samples were collected from different local markets. Routine analysis of pesticide in vegetables and equipping quality control laboratories in Gaza Strip is advised.
Keywords: Chlorpyrifos, QuChERs, HPLC, Fluorescence, MRL.
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