Spectrophotometric Determination of Proline in Aqueous Solutions

The spectrophotometric determination of proline in aqueous solutions was studied. It was shown that pH, concentration, and time of storing the solution affect its spectral properties.__________Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 8, 2005, pp. 802–805.Original Russian Text Copyright © 2005 by Davydova, Kotova, Krysanova, Selemenev.     

Specific Features of Glucoamylase Immobilization by Adsorption on Fibrous Polyelectrolytes

Some fundamental aspects of the immobilization of a hydrolytic enzyme glucoamylase via adsorption on aminocarboxylic ion-exchangers with fibrous structure were considered. The sorption capacity of amphoteric supports for the enzyme was studied in relation to the time of immobilization, concentration of hydrogen ions and the protein, and the ionic form of a polyelectrolyte. The catalytic properties of free and immobilized enzymes were compared.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 6, 2005, pp. 1003–1005.Original Russian Text Copyright © 2005 by Shkutina, Stoyanova, Selemenev.     

Effect of eluant composition on the retention of water-soluble vitamins in reversed-phase high-performance liquid chromatography

The effects of the quantitative composition and pH of water-acetonitrile eluants and temperature on the retention of water-soluble vitamins in reversed-phase high-performance liquid chromatography were studied. The retention parameters of the analytes were calculated and the limits of the applicability of the main adsorption models of retention to the test chromatographic system were discussed.     

Features of the sorption of phenylalanine by profiled ion-exchange membranes

Features of the equilibrium sorption of phenylalanine from neutral media by profiled ion-exchange membranes in a wide range of concentrations is studied under static conditions. The mechanism of phenylalanine sorption by ion-exchange membranes with profiled and smooth surfaces is discussed. It is shown that phenylalanine sorption is accompanied by the formation of spatial associative structures of the aminoacid in an external equilibrium solution, and in a solution of the membrane’s pore spaces or on its surface. The increased sorption capacity of the profiled membranes is explained by features of the microstructure of their surface and volume.     

Mechanism of Sorption Interaction between L-Alanine and Carbon Nanotubes

Russian Journal of Physical Chemistry A - A complex consisting of a model carbon nanotube and L-alanine located on its outer side surface, inside it, and at its end is simulated by quantum-chemical...     

Thermodynamics of the sorption of water-soluble vitamins in reverse-phase high performance liquid chromatography

The thermodynamics of the sorption of certain water-soluble vitamins on a C18 reverse phase from water-acetonitrile solutions of different compositions is studied. The thermodynamic characteristics of the investigated chromatographic systems are calculated. The dependences of standard molar enthalpy and changes in entropy when the sorbate transfers from the bulk solution to the surface layer on the concentration of the organic component in the mobile phase are analyzed. The boundaries for applying the main retention models describing the sorption of the investigated compounds are discussed.     

Nonempirical calculation of structural,electric and spectral characteristics of diprazine

Calculations of IR spectra, dipole moments, atomic charges, and structural characteristics of three forms of diprazine (molecular, cation and dication) were carried out. Changes in the studied characteristics in going from one form to another were analyzed.     

Sorption of sodium dodecyl sulfate by highly basic anion-exchange resins

The interaction in the system of sodium dodecyl sulfate (SDS) solution and AB-17 highly basic anion-exchange resins in OH⁻ and Cl⁻ forms were considered, and the distribution coefficients (K _d) of the substance in the resin-solution ion exchange system were calculated. It was found that K _d decreases with increasing concentration of the initial solution, reaching a maximum value at the critical micelle concentration (CMC) of SDS. The effective diffusion coefficients of the surfactant in the anion-exchange resin phase were calculated; based on the IR spectroscopy data, the mechanism of SDS absorption was proposed.