High-pressure liquid chromatography with direct injection of gas sample.

The conventional method of using liquid chromatography to determine the composition of a gaseous mixture entails dissolving vapors in a suitable solvent, then obtaining a chromatograph of the resulting solution. We studied the direct introduction of a gaseous sample into a C18 reversed-phase column, followed by separation of the components by HPLC with UV detection. Since the chromatography was performed at high pressure, vapors readily dissolved in the eluent and the substances separated in the column as effectively as in liquid samples.

[Prediction of peptide retention volumes in the gradient reversed phase HPLC].

A method of computation of retention volumes of linear peptides of known composition that contain no more than 25 amino acids in gradient reversed phase HPLC was developed. The method is suitable for various acetonitrile gradient profiles. The calculations were carried out on the basis of a statistical model, the parameters of which were experimental dependences of the retention of individual amino acids on acetonitrile concentration.

[Prediction of retention volumes and UV spectra of peptides in reversed phase HPLC].

A method for calculating retention volumes of linear peptides with known primary structures and the values of their UV absorption at chosen wavelengths in reversed phase HPLC are described. These parameters are calculated for every peptide on the basis of the contributions of its amino acid residues determining its degree of retention and its UV spectrum. The contribution values are experimentally found from chromatograms of the free amino acids obtained by multiwavelength photometric detection under the conditions of the peptide chromatography.

[Degradation of bis(2-ethylhexyl)phthalate by microorganisms of water and sediments of the Selenga river and Baikal Lake under experimental conditions].

Degradation of bis-(2-ethylhexyl)phthalate (BEHP) by microbial associations of water and bottom sediments of the Selenga River and Lake Baikal and by pure cultures of microbial species belonging to various taxa isolated from the sediments under discussion has been studied. It has been shown that intense biological degradation occurs in both water and sediments. The degrees of conversion in experimental closed systems on minimal media are 46 and 24%, respectively.

New potentialities of HPLC in pharmacopoeian analysis.

Modern status of pharmacopoeian HPLC analysis and its main shortcomings are discussed. The philosophy "special analytical method for each substance" has to be revised, and as an alternative, a principle of creation of universal methods realized by means of HPLC analyzers is proposed. A prototype of such analyzer is described.