docusate-sodium and octane

A new analytical method for determination of coenzyme Q10 (2,3-dimethoxy-5-methyl-6-decaprenyl-1,4-benzoquinone, CoQ10) in human plasma was developed based on CE using a double tensioactive microemulsion. CoQ10 was quantitatively extracted into 1-propanol/hexane and quantified by MEEKC. The microemulsion was prepared by mixing 1.4% w/w sodium bis(2-ethylhexyl) sulfosuccinate, 4% w/w cholic acid, 1% w/w octane, 8.5% w/w butanol, 0.1% w/w PVA and 85% w/w 10 mM Tris buffer at pH 9.0. The optimized electrophoretic conditions included the use of an uncoated silica capillary of 60 cm total length and 75 mum id, an applied voltage of 20 kV, room temperature and 214 nm ultraviolet detection. Selectivity, linearity, LOD, LOQ, precision and accuracy were evaluated as the parameters of validation. Owing to its simplicity and reliability, the proposed method can be an advantageous alternative to the traditional methodology for the quantitation of CoQ10 in human plasma with good accuracy and precision.

Topics: Adult; Bile Acids and Salts; Butanols; Chromatography, High Pressure Liquid; Chromatography, Micellar Electrokinetic Capillary; Electrophoresis, Capillary; Emulsions; Female; Humans; Hydrogen-Ion Concentration; Linear Models; Male; Octanes; Reproducibility of Results; Sensitivity and Specificity; Steroids; Succinates; Surface-Active Agents; Temperature; Ubiquinone

Using water/AOT/n-octane reversed micelle as the medium, the optical signal of the reactive intermediate of laccase-catalyzed oxidation of o-phenylenediamine, which was indetectable in aqueous solutions, was successfully captured. Thus online kinetic studies of the intermediate were accomplished. Two-way kinetic spectral data were acquired with stopped-flow technique. By resolving the data with global analysis software, both the kinetic curves and the absorption spectra of the components involved in the reaction process were simultaneously obtained. The whole reaction in the reversed micelle was proved to be composed of two successive steps, an enzymatic generation of the intermediate and a following nonenzymatic decay of the intermediate. A consecutive first-order kinetic model of the whole reaction was confirmed. The influences of microenvironmental factors of the medium (such as the pH value of the water pool and the water/AOT ratio) on the detection of the intermediate were also investigated.

Topics: Catalysis; Enzyme Activation; Enzyme Stability; Kinetics; Laccase; Micelles; Octanes; Oxidation-Reduction; Phenylenediamines; Solvents; Spectrophotometry; Succinates; Surface-Active Agents; Water