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, ??-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?C0.01, 0.001?C0.01 and 0.001?C0.02?mg/ml for fenpropathrin, ??-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, ??-cyhalothrin, and deltamethrin, respectively. The recoveries of fenpropathrin, ??-cyhalothrin, and deltamethrin at three concentration levels spiked to tomato were found to be in range 85.77?±?1.52?C95.61?±?3.65%, 91.77?±?4.34?C98.59?±?2.46% and 92.61?±?2.46?C98.04?±?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, ??-cyhalothrin, and deltamethrin.     

Tailoring the structural,electrical, and optical features of Erbium(III)-Tris(8-hydroxyquinolinato) nanostructured films for optical applications: effect of film thickness

This paper elaborates on the thickness-dependent structural, optical, and electrical properties of Erbium(III)-Tris-8-hydroxyquinolinato (ErQ3) films. The surface morphology reveals the grains that consolidate to make denser films with increasing film thickness. The ErQ3 grain sizes increased from 80 to 187 nm as the thickness increased from 80 to 190 nm. From XRD analysis, the ErQ3 films are partially crystallized with only one peak at 2θ?=?9.80° and a plateau in the range of 20–40°. Electrical measurement of ErQ3 films showed that the electrical conductivity had a strong dependence on film thickness. Transmittance and reflectance measurements showed that the films exhibited a 2.60 eV bandgap, and it does not depend on the thickness of the film. Also, the dispersion of the refractive index was analyzed to determine the essential parameters. The nonlinear optical parameters such as nonlinear refractive index and third-order nonlinear optical susceptibility were calculated by Miller's principles.