Miniaturized counter current liquid–liquid extraction for organophosphorus pesticides determination

In the present work, a simple, rapid, sensitive and economical sample pre-treatment technique; miniaturized counter current liquid–liquid extraction was developed for the determination of organophosphorus pesticide (OPP) residue in water samples and compared with conventional dispersive liquid–liquid microextraction. Gas chromatography–flame ionization detector (GC/FID) was used for OPP quantification. Two OPPs (diazinon and malathion) were selected as model compounds and the proposed methods were carried out for their preconcentration from water samples. The presented method was based on dispersive liquid–liquid extraction with methanol containing butyl acetate as a solvent with density lower than water. After phase separation, butyl acetate was injected into the GC/FID instrument. The linearity was obtained in the concentration range of 0.4–1000.0 μg L−1 and correlation coefficients were in the range of 0.999–0.997 for diazinon and malathion, respectively. The limits of detection (LODs), was based on signal-to-noise ratio (S/N) of 0.1 μg L−1 for two pesticides

Metal ion promoted degradation mechanism of chlorpyrifos and phoxim

This study evaluate the degradation of the two organophosphorus pesticides: chlorpyrifos and phoxim in the presence of Ag+ at fixed initial concentration and temperature. Chlorpyrifos and phoxim were used as model compounds to develop experimental methods for the investigation of kinetic and degradation pathways. In order to determine what metabolites will be formed after degradation we used 31P NMR. Chlorpyrifos and phoxim were found to degrade in the presence of Ag+ and the result shown in lower chlorpyrifos to Ag+ ratio (<8), only one product formed and its concentration increased versus time. Degradation of chlorpyrifos and phoxim in methanolic solution in the presence of Ag+ followed first-order exponential decay kinetics, and the half-life (t1/2) of chlorpyrifos and phoxim are 693 and 1155, respectively

Synergistic effects of Para

Background and aim: Post-operative pain is considered an important complication of Intravenous regional anesthesia (IVRA) which is gaining popularity especially for surgeries on upper limbs. Methods: The present double blind randomized clinical trial was conducted on 60 candidates of upper limb surgeries aged between 20 and 60 years who were of ASA classes 1 or 2. Subjects were randomly assigned to 4 groups: the first group was treated solely with 3 mg/kg of Lidocaine. The second and third groups received the same amount of Lidocaine plus 8 mg of Dexamethasone or 300 mg of Paracetamol respectively and for the fourth group a combination of all medications was used. For all patients, Lidocaine was diluted with normal saline until a total volume of 40 cc was reached. Onset of Sensory and motor nerve blocks, severity of post-operative pain and amount of mepridine consumption in the first 24 h after surgery were assessed. Results: Onset of Sensory and motor nerve block was significantly accelerated in the fourth group (p < 0.01). Post-operative pain and analgesic consumption were significantly reduced in the fourth group when compared with the other groups (p < 0.05). Conclusion: A combination of Paracetamol and Dexamethasone significantly enhances the analgesic effect of Lidocaine in IVRA by accelerating the establishment of both the sensory and motor nerve blocks and prolonging the period of analgesia as well as improving the quality of analgesia and reducing the need for analgesic medications during and after the operation