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Water soluble poly (vinyl alcohol) (PVA) was used to prepare the enzyme membranes of acetylcholinesterase (AChE) for electrochemical assaying methyl parathion in water insoluble organic solvent. The immobilized enzyme was separated from electrode for the development of enzyme inhibition-based bioassays. This assay is simple and convenient where enzyme membrane is applicable for single use and the electrode for repeated use. The enzyme membranes can be used handily piece by piece and the released AChE performs catalytic reaction homogeneously. The inhibition percentage of AChE increases with the concentration of methyl parathion ranging from 0.1 to 1 mg/mL. [ABSTRACT FROM AUTHOR]

Effects of three organic solvents, viz. methyl cellosolve, acetonitrile, and formamide, on the micellization process of Gemini surfactant pentamethylene-1,5-bis(tetradecyldimethylammonium bromide) aqueous solutions, with the volume percentages of the organic solvents up to 50%, have been investigated conductometrically. The studies were made at different temperatures and the data were used to find out different micellization parameters. From the study, it was observed that, although an increment in the amount of the organic solvents delays the micellization, the increase in the critical micelle concentration (cmc) is comparatively less below 20%(v/v) showing the predominance of water character in the bulk phase at lower compositions of the organic solvents. Applying equilibrium model for micelle formation, various thermodynamic parameters were also calculated from the temperature dependence of the cmc values and the results show that the micellization process becomes less spontaneous as the volume % of the organic solvent increases in the system due to the action of water-organic solvent mixed media as better solvent than pure water (solvophobic effect) for the studied Gemini molecules. [ABSTRACT FROM AUTHOR]