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a sulfonamide fragment but also conformational equilibrium among these types of intramolecular interactions are essential for the manifestation of high efficiency in suppressing HIV-infection in cell culture.Introduction. Many derivatives of aminophenols (AP) are known to be effective antioxidants that are capable of changing the course of free-radical processes [1]. These compounds also have traditional applications as stabilizers of industrial organic materials and as food preservatives [2,3]. They exhibit high efficiency for prevention and treatment of pathologies due to disorders in the human antioxidant system [4] and as antiviral agents against herpes simplex and flu A virus [5][6][7][8][9]. AP derivatives that suppress HIV-infection in cell culture were recently synthesized [10].The pharmacological properties of AP are related to their effect on the course of free-radical processes in biological systems. Steady-state radiolysis and IR spectroscopic methods found that the antioxidant properties of AP are enhanced when the hydroxyls in the molecules are free and diminished upon forming various types of intramolecular hydrogen-bonds (IHB) [11]. As a rule, reactions involving active oxygen species occur nonselectively. Their occurrence in biological systems can damage both the cells themselves and viruses incorporated into them if highly active antioxidants are used.The question of which AP derivatives that are added to biological systems can change the course of free-radical reactions so that an effective and stable antiviral effect is obtained remains open. Therefore, it is important in principle to study properties of individual molecules such as the ability to form IHB because the type of IHB found in the AP is frequently related to their antiradical and antiviral activity [12,13].Herein IR-Fourier spectroscopy is used to study intramolecular interactions (IMI) in CCl 4 solutions of five structurally similar AP derivatives, 4,6-di-tert-butyl-2-(phenylamino)phenol (AP I), N-(3,5-di-tert-butyl-2-hydroxyphenyl)acetamide (AP II), N-(2-hydroxy-3,5-di-tert-butylphenyl)-4-methylbenzenesulfonamide (AP III), N-(2-methoxy-3,5-di-tert-butylphenyl)-4-methylbenzenesulfonamide (AP IV), and N-(2-hydroxy-3,5-di-tert-butylphenyl) methanesulfo-namide (AP V):

The application of laser spectrochemical analysis to testing for basic compounds and nutritious/toxic elements in soil has been reviewed. A combined laser-spark approach has been applied for the rapid measurement of the carbon content in soil. Spectra have been excited both directly in a laser-ablation plume and by passing a pulsed electric discharge through the plume. The emission spectrum intensity in the combined plasma is considerably higher. The application of a complex of methods to carbon determination in soil has shown that in fact the data on the humus content usually obtained in agrochemical practice by a conventional method of carbon oxidation by potassium dichromate need to be corrected taking into account the possibility of incomplete oxidation of organic matter in soil. The efficiency of various double-pulse LIBS applications has been demonstrated in solving a number of environmental problems such as the determination of heavy and toxic metals in soil and the detection of sulfur in coal. The instrumentation and analytical procedures have been proposed and optimized for rapid control of the chlorine content in plant samples. The technique can be easily extended to ecological monitoring of toxic elements and heavy metals in any biogenic material.Introduction. Laser methods for analyzing the composition of soil, ore, minerals, and related materials have been developing rapidly for the last decade. A comprehensive review of these methods reveals that the technology for performing the analytical procedures, the equipment, and the techniques for processing results are similar. The employed methods are based on emission spectroscopy, fluorescence, Raman scattering, IR reflectance from the samples, etc. Laser-induced breakdown spectroscopy (LIBS) is promoted as a primary technique. This method was developed very early [1-4] and is sufficiently validated for solving various practical problems such as quality control of industrial products [5], processes [6], the environmental situation [7], water resources [8], and the composition of ores and minerals [9] in addition to problems in criminology for detecting explosives [10], pharmacology [11], archeology and art [12], and biological samples [13]. This method is used in agricultural chemistry to determine the soil content of carbon, which characterizes the humus content, and several nutritious elements and toxins [14][15][16]. For this, LIBS factors such as simple sample preparation for analysis, rapid processing of results and their distribution, and prospects for determining the soil composition under field conditions are important [17].Because soil has a complicated background composition, it is analyzed as a rule by calibrating instruments using certified samples (standards). These standards can differ in complexity even for solving similar problems depending on the matrix of samples subject to analysis. For example, the determination of C in chernozem and loamy soils and rocky and peaty ores cannot be carried out using single certified samples. Standards ...