O. G. Larionov

Chromatography: Method of investigation of surface chemistry and interface processes

This paper discusses application of gas and liquid chromatography to studies of surface chemistry and various materials. Examples of studying adsorption processes from gas and liquid media with application of the chromatography technique are given. It is shown that the information on the structure of the material obtained using the chromatography technique allows predicting the regularities of chromatographic retention for molecules of different structures and various sorbents. The chromatography technique is frequently used in studies of nanomaterials and stable nanoparticles. It is shown that the chemical properties of surfaces modified by nanoparticles can be advantageously used in gas and liquid chromatography techniques. Much attention is given to molecular statistical calculations of adsorption on carbon sorbents in gas and liquid chromatography. The possibilities of the technique regarding prediction of retention of various sorbates and specification of structural parameters of molecules are demonstrated. Methodological and preparative aspects of a new area, micellar chromatography of nanoparticles, are considered. Options of liquid chromatography for separation, including preparative separation, identification, and classification, are shown.

Retention Indices as the Most Reproducible Retention Parameters in Reversed Phase HPLC. Calculation for Hydrophilic Phenolic Compounds Using Reference n‐Alkyl Phenyl Ketones

Abstract A comparison of various presentation forms of retention parameters measured in multi‐step gradient elution regimes in reversed phase HPLC indicates that retention indices in the scale of n‐alkyl phenyl ketones (so‐called Smith′s RI system) have the maximal reproducibility. However, the determination of these parameters for most hydrophilic compounds eluted before the first reference acetophenone (RI=800) implies their calculation by extrapolation, that can lead to the high irreproducibility of results, especially in regimes with initial isocratic stages followed by fast gradient elution. This fact explains the necessity of elaboration of a new calculation method based on the extrapolation of retention concentrations, which provides the appropriate interlaboratory coincidence of RI values at least within the range 600–800 i.u. Using this algorithm, retention indices for about 60 phenolic compounds have been determined, that permits us to identify them in complex mixtures of natural plants extractive substances using HPLC without corresponding reference samples.

Physicochemical properties of surfaces of various nanomaterials according to gas-chromatography data

The thermodynamic characteristics of adsorption on original and modified silica and ultradispersed diamond adsorbents are determined using gas chromatography. The contributions of the dispersion and specific donor-acceptor interactions to the total adsorption energy are estimated and the relation between the properties of the modified specimens and the surface treatment is found. Based on the data obtained, donor and acceptor characteristics of the adsorbent surfaces studied are estimated.

Study of nanoparticles synthesized in reverse micelles using liquid chromatography method

Liquid chromatography, which makes it possible to investigate interphase processes, is an additional method for studying inverse micellar systems without changing their properties in the process of sample preparation. In the case of using these systems to synthesize nanoparticles (NPs), it becomes possible to determine their adsorption characteristics, to investigate the processes of modifying surface adsorbents by NPs, to determine their sizes, and to divide them into fractions according to their sizes and surface properties of the micelles. The method is simple and rapid and permits one to use standard, relatively inexpensive equipment and can be applied in many physicochemical studies of NPs synthesized in micellar solutions.

HPLC in the study of radiation-chemical changes in the composition of wines

The study of radioprotective properties of wine related to their ability to regulate redox processes and resist oxidative stress caused by exposure to ionizing radiation and other factors in living systems is of current interest. Physico-chemical approach, including the use of such methods as chromatography for research on the effect of these factors is underdeveloped. In this paper, the HPLC method was used to identify products of γ-radiolysis of serotonin and other phenolic components of wines and calculate the degrees of conversion of the starting compounds. These data are necessary for measuring the radiation resistance of biologically active compounds, including serotonin, since recently the radiation-chemical methods of sterilization of medicinal preparations on their basis are widely used. Determination of products of radiation-chemical reactions of bioactive compounds is important in the problem of studying the mechanism of the redox reactions in biological systems with different degrees of organization.