Sensitive spectrophotometric methods for determination of some organophosphorus pesticides in vegetable samples

Three rapid, simple, reproducible and sensitive spectrophotometric methods (A, B and C) are described for the determination of two organophosphorus pesticides, (malathion and dimethoate) in formulations and vegetable samples. The methods A and B involve the addition of an excess of Ce4+ into sulphuric acid medium and the determination of the unreacted oxidant by decreasing the red color of chromotrope 2R (C2R) at a suitable lmax = 528 nm for method A, or a decrease in the orange pink color of rhodamine 6G (Rh6G) at a suitable lmax = = 525 nm. The method C is based on the oxidation of malathion or dimethoate with the slight excess of N-bromosuccinimide (NBS) and the determination of unreacted oxidant by reacting it with amaranth dye (AM) in hydrochloric acid medium at a suitable lmax = 520 nm. A regression analysis of Beer-Lambert plots showed a good correlation in the concentration range of 0.1-4.2 μg mL−1. The apparent molar absorptivity, Sandell sensitivity, the detection and quantification limits were calculated. For more accurate analysis, Ringbom optimum concentration ranges are 0.25-4.0 μg mL−1. The developed methods were successfully applied to the determination of malathion, and dimethoate in their formulations and environmental vegetable samples

METHODS FOR DETERMINATION OF

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Accuracy of three-dimensional multislice view Doppler in diagnosis of morbid adherent placenta

Photograph used for a story in the Daily Oklahoman newspaper. Caption: "Guthrie flood waters carry a 100-foot long frame office buidling downstream before it broke in half, leaving a portion of roof showing above the water. Water is 7 feet in street. O-12-27-59: Road waters raged through many sections of the state as heavy autumn downpours created water crises. This picture shows some of the flood waters at Guthrie.

Influence of Mo+2 ion concentration on crystallization, microstructure, crystal imperfection and morphology of WO3 sprayed thin films

Compositional dependence of microstructure and morphological properties of Mo _x W _1−x O _3 (0.2 ≥ x ≥ 0.0 at. %) thin films was studied. MoWO _3 films were deposited by chemical spray pyrolysis technique on pre-heated glass substrates at 400 °C and the sedimentation rate was kept constant at 70 ml min ^−1 with the deposition time fixed at 10 min to keep the film thickness constant at about 650 ± 5 nm. The prepared thin films were studied using x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive x-ray analysis (EDAX) techniques. The nature of the as-deposited films displayed by XRD showed beyond a reasonable doubt that they are amorphous. After thermal annealing at 500 °C for 2 h, all samples will be transferred to a polycrystalline having a triclinic structure. The microstructural parameters of the pure and doped samples were measured, using different methods and a comparison between them to determine the accuracy percentage of the measurement of these methods. The results also showed that the average crystallite size of the films decreased from 24 to 12 nm, on the contrary the internal microstrain increased from 23 × 10 ^−3 to 30 × 10 ^−3 with the addition of Mo element in WO _3 . Field emission scanning electron microscopy (FE-SEM) analysis also revealed that Mo dopant caused significant changes in the surface morphology of the films as well as an increase in particle size with increasing molybdenum concentration. The EDX results exhibited that the percentages of the isotropic elements Mo _x W _1−x O _3 agree well with those determined by atomic weight. In general, the results obtained in this study confirm that Mo _x W _1−x O _3 with these properties, is suitable for photovoltaic and optoelectronic applications