A Gas Chromatographic Method with Electron-Capture Detector (GC-ECD) for Simultaneous Determination of Fenpropathrin, λ-Cyhalothrin, and Deltamethrin Residues in Tomato and Its Applications to Kinetic Studies After Field Treatment

In this study, simultaneous determination of fenpropathrin, lambda-cyhalothrin, and deltamethrin in tomato fruit (Lycopesicon esculentum) grown in Khartoum, Sudan, was carried out using gas chromatography with electron capture detector (GC-ECD).The method was linear in the range of 0.001-0.01, 0.001-0.01 and 0.001-0.02 mg/ml for fenpropathrin, lambda-cyhalothrin, and deltamethrin, respectively. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.0012 and 0.0041, 0.0013 and 0.0041 and 0.0026 and 0.0087 mg/ml for fenpropathrin, lambda-cyhalothrin, and deltamethrin, respectively. The recoveries of fenpropathrin, lambda-cyhalothrin, and deltamethrin at three concentration levels spiked to tomato were found to be in range 85.77 +/- 1.52-95.61 +/- 3.65%, 91.77 +/- 4.34-98.59 +/- 2.46% and 92.61 +/- 2.46-98.04 +/- 2.93%, respectively. The kinetic study of the degradation of all pesticides was performed and the ultimate evaluation of the kinetic data revealed a pseudo first order kinetics pattern for fenpropathrin, lambda-cyhalothrin, and deltamethrin.