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Determination of serum glucose with glucose oxidase immobilized onto affixed egg membrane

2016-07-20T06:45:50Z

Title: Determination of serum glucose with glucose oxidase immobilized onto affixed egg membrane Authors: Sharma, Minakshi; Kumar, Vijay; Pundir, C S Abstract: A reusable strip of glucose oxidase (OOD) from Aspergillus niger was prepared by immobilizing the enzyme onto egg albumin membrane affixed on a plastic strip with a conjugation yield of 1.5 mg/cm² and 66% retention of their initial specific activity. The immobilized enzyme showed maximum activity at pH 7.0 when incubated at 37°C for 15 min. A method for discrete analysis of serum glucose was developed employing this strip. The minimum detection limit of the method was 5 mg/dL. Within and between assay coefficient of variation (CV) for serum were <5 and <6%. A good correlation (r=0.972) was found between glucose values obtained by commercial enzymic colorimetric method employing free GOD and the present method. No significant loss in the strip activity was observed after its 150 regular uses for a period of 40 days, when stored in reaction buffer at 4°C. The method has advantage over commercial enzymic colourimetric method that it provides reuse of glucose oxidase with ease. Page(s): 544-548

Preparation and some properties of lithium vanadium bronzes

2016-07-20T06:45:49Z

Title: Preparation and some properties of lithium vanadium bronzes Authors: EI-Sayed, AM; Mousa, S M A Abstract: Lithium vanadium bronzes with composition formula Li_x V₂O₅ (0.04 ≤ x ≥ 0.92) have been prepared by solid-state reaction at 650°C in argon atmosphere. The products were characterized by X-ray powder diffraction and IR spectroscopy. The results reveal that four phases namely α-, β-, βʹ- and γ-phase are present in the studied range. The magnetic susceptibility for the investigated samples was measured using Gouy’s method. The values of the effective magnetic moments as calculated from experimental data indicate the presence of V⁴⁺ ions in all samples. The electrical conductivity as a function of temperature and lithium content was measured in the temperature range from-room temperature to 483 K. The electrical conductivity of the samples is found to be affected by lithium content. The values of the electrical conductivity increase with temperature for the investigated samples. The electronic and ionic conductions are discussed. Page(s): 372-377

Synthesis and analytical application of Fe(III) based heteropoly acid cation exchangers

2016-07-20T06:45:49Z

Title: Synthesis and analytical application of Fe(III) based heteropoly acid cation exchangers Authors: Geetha, V; Janardanan, C Abstract: New inorganic ion exchangers based on Fe(III) namely ferric tungstomolybdate, ferric tungstosilicate, ferric tungstovanadate have been synthesized and characterized on the basis of chemical composition. The ion exchange capacity, pH titrations, distribution Coefficients, FTIR, TGA and thermal stabilities. The ion exchangers were found to be stable in 1.0 M mineral acids and 1.0 M metal chloride solutions. The formulae proposed for the exchangers are Fe₂O₃.2WO₃.8H₂O; Fe₂O₃.2WO₃.2SiO₂.9H₂O and Fe₂O₃.2WO₃.V₂O₅.10H₂O respectively. Based on the difference in K_d values, some analytically important separations of metal ions have been achieved. The important mixtures analyzed are Al³⁺ - Mg²⁺, Co²⁺- Pb²⁺, Hg²⁺ - Pb²⁺, Ni²⁺- Pb²⁺, Cd²⁺ - Pb²⁺ and Cu²⁺ - Pb²⁺. Page(s): 185-188

Acridine orange and chlorite reaction — An indicator reaction for the trace determination of Ru(III)

2010-01-07T16:30:24Z

Title: Acridine orange and chlorite reaction — An indicator reaction for the trace determination of Ru(III) Authors: Bhagwat, V W; Vijay, Rajani; Jonnalgadda, S B; Pare, Brijesh Abstract: Catalysis by transition metal ions plays an important role in understanding the mechanistic aspects of a particular redox reaction. Ru(III) acts as an efficient and potential catalyst in many redox reactions. Hence the use of Ru(III) chloride as a homogeneous catalyst in acidic medium is of present interest. Based on the highly selective catalytic efficiency of Ru(III) on the oxidation of acridine orange {3,6-bis (dimethylamino) acridine zinc chloride double salt}(AO⁺) by acidic chlorite, a fixed-time kinetic analytical procedure for determination of Ru(III) is developed. The lowest determination limit attainable with the developed method is 1.01 ng/mL. The method allows determination of Ru(III) with no interference from a wide range of cations. Tolerance ratios have also been computed. With excess concentration of reactants, both un-catalyzed and catalyzed reactions follow a pseudo-first order kinetics in [AO⁺], fractional order kinetics in oxidant and first order kinetics in catalyst [Ru(III)]. The rate coefficient of the un-catalyzed reaction is 4.4510^-4s^-1 while the catalytic constant for the catalyzed reaction is 8.0010^-4s^-1. Retarding effect of increasing ionic strength suggests the involvement of oppositely charged species in rate determining step. A tentative mechanism has also been proposed based on the results of variation of various factors. Page(s): 644-647