近年国内固相萃取-色谱分析的进展

对近两年国内各个领域的学者在使用固相萃取做样品前处理的色谱分析方面的研究和应用作了综述, 这一综述包括10个部分: 1. 国内近两年有关固相萃取的综述报告;2. 固相萃取-色谱分析在水质分析中的应用;3. 固相萃取-色谱分析在奶制品和肉类食品分析中的应用;4. 固相萃取-色谱用于蔬菜和水果中有害物质分析的应用;5. 固相萃取-色谱用于粮食和其他食品中有害物质分析的应用;6. 固相萃取-色谱在血药浓度、体液及组织中有害物质分析中的应用;7. 固相萃取-色谱在药物分析中的应用;8. 固相萃取-色谱在其他使用色谱分析中的应用;9. 基质固相分散在色谱分析中的应用;10. 分子印迹SPE在样品前处理中的应用.     

Carbohydrates of cultivated varieties ofAlthea rosea

The polysaccharides of three cultivated varieties ofAlthea rosea have been investigated. The amounts of water-soluble polysaccharides and pectin substances in various organs of the plant have been determined. It has been shown that the maximum amount of water-soluble polysaccharides and pectin substances is present in the flowers. Their monosaccharide compositions have been studied. The physicochemical characteristics of the pectin substances are given.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent. A. Sadykov Institute of Bioorganic Chemistry, Academy of Sciences of the Republic of Uzbekistan. Tashkent. Institute of Botany, Academy of Sciences of the Republic of Uzbekistan, Tashkent. Translated from Khimiya Prirodnykh Soedineii, No. 5, pp. 643–646, September–October, 1993.     

Investigation of the electrophoretic composition of the proteins of cottonplant pollen grains

We have studied the proteins of the pollen and ovules of the cotton plant. No differences were observed in the electrophoregrams of the proteins from Gossypium hirsutum L. and from G. barbadense L. In the spectrum of the pollen proteins, the main components quantitatively were polypeptides with molecular masses of 34, 44, 47, and 52 kDa. The species G. raimondii Ulbr. differed considerably, with the main polypeptides quantitatively having molecular masses of 27, 36, 46, and 58 kDa. In representatives of genomic group C, interspecies differences were observed in the protein spectra of the pollen. No appreciable differences were observed spectrally in the proteins of the cottonplant ovules.Biolog Scientific Production Combine, Academy of Sciences of the Republic of Uzbekistan, Republic of Uzbekistan, Institute of Genetics, Academy of Sciences of the Republic of Uzbekistan, Republic of Uzbekistan, Tashkent ul. F. Khodzhaeva, 28. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 454–456, May–June, 1995. Original article submitted September 13, 1994.     

Chemical composition of the essential oil ofArtemisia glabella

The results are given of the gas-chromatographic analysis in a nonpolar capillary column, after preliminary separation by means of adsorption chromatography on alumina, of samples of the essential oils of three populations of the endemic speciesArtemisia glabella Kar. et Kir. (Asteraceae) of Kazakhstan. The complex component composition of the samples of essential oils was practically independent of the conditions of the growth site. The results obtained witness a chemosystematic difference betweenA. glabella andA. obtusiloba.Institute of Phytochemistry, Academy of Sciences of the Republic of Kazakhstan, Karaganda, fax (3212) 433144, e-mail: arglabin@phyto.karaganda.su. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 193–196, March–April, 1999.     

Theoretical conformational analysis of the methylamides of N-acetyl-L-alanyl-L-proline and N-acetyl-L-prolyl-L-alanine. I

Summary 1. The most preferred forms of the compounds Ac-L-Ala-L-Pro-NHMe participating in a conformational equilibrium are characterized by both the trans and the cis configurations of the tertiary amide group.2. The formation of intramolecular hydrogen bonds in the conformations of Ac-L-Ala-L-Pro-NHMe realized is unlikely.3. The conformational states of the compounds Ac-L-Pro-L-Ala-NHMe with the trans configurations of the tertiary amide group are most probable. In nonpolar media a probability of the formation of structures with hydrogen bonds is high.4. The conformational distribution of the fragments -X-Pro- and -Pro-X- in proteins agrees satisfactorily with the calculated values of the energy of the optimum forms of the corresponding dipeptides, Ac-L-Ala-L-Pro-NHMe and Ac-L-Pro-L-Ala-NHMe.M. M. Shemyakin Institute of Bioorganic Chemistry, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 618–626, September–October, 1975.     

Ion separation in imperfect fields of the quadrupole mass analyser Part IV. Theoretical applications

The theoretical aspects of ion separation in imperfect fields of the quadrupole mass analyser in the form of examples of practical simulation is the subject of this paper. The simulation results reveal that the field distortions cause an additional increase in energy spread while the ions pass the fringing fields. This phenomenon leads to an appearance of peak “shadows” in a mass spectrum. The location of major and precursor peaks in the mass spectrum depends on the relative deviation of their amplitudes of energy distribution. Analysis of distortions resulting from harmonic composition of the voltage waveform shows that the r.m.s. value of stable trajectories is proportional to that of an r.f. voltage which is independent of phase. The fluctuations of a general harmonic composition exert an influence on the transmission which depends more on first harmonic composition than on those of higher harmonics. Transmission is an exponential function of a general harmonic composition whereas with respect to phase it is an oscillatory function.     

Method for efficient computation of the density of states in water-explicit biopolymer simulations on a lattice

We present a method for fast computation of the density of states of binary systems. The contributions of each of the components to the density of states can be separated based on the conditional independence of the individual components' degrees of freedom. The conditions establishing independence are the degrees of freedom of the interfacial region between the two components. The separate contributions of the components to the density of states can then be calculated using the Wang-Landau algorithm [Wang, F.; Landau, D. P. Phys. Rev. Lett. 2001, 86, 2050]. We apply this method to a 2D lattice model of a hydrophobic homopolymer in water that exhibits protein-like cold, pressure, and thermal unfolding. The separate computation of the protein and water density of states contributions is faster and more accurate than the combined simulation of both components and allows for the investigation of larger systems.     

Herbicidal activity of culture filtrates of Trichoderma spp. against two problematic weeds of wheat

The herbicidal potential of culture filtrates of four Trichoderma spp., namely Trichoderma harzianum Rifai, Trichoderma pseudokoningii Rifai, Trichoderma reesei Simmons and Trichoderma viride Pers., was evaluated against two problematic weeds of wheat, Phalaris minor L. and Rumex dentatus L. In laboratory bioassays, generally, metabolites of all four Trichoderma species significantly reduced various root and shoot growth parameters of the two target weed species. The original concentrations of the culture filtrates of all Trichoderma spp., except T. harzianum, significantly reduced various parameters of root and shoot growth of wheat seedlings. In a foliar spray bioassay, the culture filtrates of all four Trichoderma spp. significantly diminished root and shoot biomass of R. dentatus. The effect of these filtrates on the shoot growth of P. minor and wheat was not significant. Culture filtrates of the four Trichoderma species were successively extracted with butanol, n-hexane, chloroform and ethyl acetate. In detached leaf injection bioassays, n-hexane fractions (3 mg mL(-1)) of T. pseudokoningii, T. reesei and T. viride, and ethyl acetate fractions of T. horzianum and T. pseudokoningii were found to be toxic against R. dentatus. This study concludes that the culture filtrates of Trichoderma species have herbicidal potential in the control of R. dentatus.     

Protein content, activity and amino acid composition of proteinase inhibitors of seeds of some varieties of pea and their hybrids

The results are given of a study of the quantitative content of protein in the seeds of some pea varieties and mutants, the activity of the total inhibitor proteins, and correlations of their activity with the protein content of the seeds and the amino acid compositions of the proteinase inhibitors. Considerable differences have been found in the amounts of a number of amino acids of the protein inhibitors of parental varieties and mutants of the pea, the amounts of serine, glutamic acid, alanine, and valine correlating positively with the inhibitor activity.Institute of Plant Physiology and Biophysics, Tadzhik SSR Academy of Sciences, Dushanbe. V. I. Nikitin Institute of Chemistry, Tadzhik SSR Academy of Sciences, Dushanbe. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 399–404, May–June, 1988.     

Porous Phosphates of Trivalent Metals: Problems of Their Synthesis and Application

Abstract

Porous phosphates are compounds with a branched system of pores, such as X-ray amorphous xerogels of metalphosphates and crystalline phosphates of zeolite type. Having generalized extensive experimental data about the conditions of Al-, Fe-, Cr-, Ga-, In-, Y-phosphate hydrogels synthesis we found the influence of a number of factors on the rates of their formation, stability of structures and the porosity character of xerogels. The mechanism of porous structure formation of xerogels of metalphosphates has been proposed. The problems connected with the regulation of porous structure of xerogels have been discussed. The formation of porous crystalline aluminophosphates of zeolite type has been accomplished through a number of stages. The nature of alkyl ammonium bases influences the direction of the crystallization process and the type of the structure. It was noted that the stoppind of crystallization on different stages of synthesis gives the possibility to obtain new molecular sieves. Thermal changes and sorption properties of aluminopnosphates of zeolite type have been studied. During the process of removing organic cations the formation of secondary porosity was established. The effectiveness of applying porous metalphosphates in catalysis and adsorption processes has been showed.     

Electrohydraulic effect in heterodisperse water-plant systems. II. Chemical nature of the suspended particles

On the basis of the results of acid hydrolysis, chromatographic analysis of the hydrolysates, and a study of IR spectra, it has been established that the suspended particles liberated under the action of electrohydraulic shocks on heterodisperse water—plant systems consist of small fragments of the lignocarbohydrate complex of the plant tissue.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent. FAX (3712) 62 73 48. Division of Wood Chemistry, Irkutsk Institute of Organic Chemistry, Siberian Division of the Russian Academy of Sciences. Institute of Solar and Terrestrial Physics, Siberian Division of the Russian Academy of Sciences, Irkutsk, FAX (395-3) 46 25 57. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 435–439, May–June, 1994.     

Exoglycans of Yersina pseudotuberculosis

Summary 1. From a culture medium of strain 12 ofYersinia pseudotuberculosis of subtype IB a mixture of exoglycans has been isolated which consists of acidic heteropolysaccharides bound ionically to a protein component.2. The yield and monosaccharide composition of the exoglycans produced depend on the conditions of growth and the form of the colonies.3. The exoglycans of the local strain No. 12 and of a standard strain (No. 159) ofY. pseudotuberculosis of subtype IB contain monosaccharides (galactose, glucose, mannose, xylose, arabinose, fucose, glucuronic acid, glucosamine) and differ only by the ratio of the monosaccharide residues.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center of the Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 315–321, May–June, 1975.     

BOOK REVIEWS

Advances in Photochemistry, Volume 14. Edited by D. H. Volman, G. S. Hammond and K. Gollnick. Wiley/Interscience, New York, 1988
Department of Chemistry Korea Advanced Institute of Science and Technology P.O. Box ISO Cheongyangni Seoul 130–650, Korea
Photochemistry, Volume 18. Senior Reporter–D. Bryce-Smith. The Royal Society of Chemistry, London, August 1987
Department of Chemistry Korea Advanced Institute of Science and Technology P. O. Box 150 Chongyangni Seoul 130–650, Korea
Photochemistry, Volume 19. Senior Reporter–D. Bryce-Smith and A. Gilbert. The Royal Society of Chemistry, London, July 1988
Department of Chemistry Korea Advanced Institute of Science and Technology P.O. Box 150 Chongyangni Seoul 130–650, Korea
Laser Picosecond Spectroscopy and Photochemistry of Biomolecules. Edited by V. S. Letokhov, Adam Hilger, Bristol and Philadelphia
University of Chicago Department of Chemistry Chicago, IL 60637 USA
The Science of Photobiology. Second Edition. Edited by Kendric Smith. Plenum Press, New York, NY
Department of Biochemistry. 113 Biochemistry Hall University of Nebraska Lincoln.' NE 6X583–071H USA     

Transient Processes in the Disperse System with Coagulation and Aggregate Disintegration

The kinetics of transition of the coagulating disperse system with aggregate disintegration into a new equilibrium state was considered in the course of the disturbance of the earlier existing equilibrium, which is caused by a change in the flow shear rate. An analysis carried out on the basis of a two-fraction model of dispersed phase [B.M. Dolgonosov, Kolloid. Zh., 2001, vol. 63, no. 1, p. 32] has shown that the spectrum of fine-fraction particles is a superposition of the initial and final states with the superposition coefficients dependent on the current value of the average mass of coarse-fraction particles (large-size aggregates). The spectrum of large aggregates in the form of a quasi-equilibrium distribution of a Gaussian type with time-dependent parameters was obtained. The variation of superposition coefficients and parameters of the spectrum of large aggregates with time was calculated. The conditions of applicability of the suggested approach were discussed.     

Selective oxidation of ethylbenzene by dioxygen in the presence of complexes of nickel and cobalt with macrocyclic polyethers

The oxidation of alkylarenes by dioxygen in the presence of complexes of nickel and cobalt with macrocyclic ethers 18-crown-6 and 15-crown-5 was studied. The conditions for selective catalytic oxidation of ethylbenzene to α-phenylethyl hydroperoxide were determined. The kinetics of the accumulation of all oxidation products was studied. The order of the formation of the products at different stages of chain oxidation was determined. The activity of the complexes at the elementary stages of the chain oxidation of ethylbenzene is discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 689–693, April. 1997.     

The use of the acetolysis reaction for the investigation of natural phospholipids

Summary 1. When the acetolysis reaction is used to study the molecular types of natural phospholipids or to determine the bound glycerol, the possibility of a distortion of the results of analysis through the formation of by-products must be taken into account.2. In order to prevent the formation of aldehyde acylals, the phospholipids undergoing analysis must first be freed from plasmalogens.3. To prevent the formation of derivatives of propane-1,2-diol in the hydrolyzates of the acetolysis products of the phospholipids, the initial lipids must be freed from chloride ions.M. M. Shemyakin Institute of Biochemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 30–37, January–February, 1976.     

Analysis of metastable defocusing spectra of lycoctonine bases having 7,8-methylenedioxy groups

The parameters of the MD spectra of the fragmentary ions of 21 lycoctonine alkaloids with 7,8-MDOGs have been investigated. On this basis, the monotypicity of the main fragmentation processes characteristic for the individual groups of compounds have been confirmed. A decrease in the number of common group characteristics of the MD spectra of the ions arising as the result of multistage breakdown processes is caused by alternative methods for their formation. This is not shown only by the doublet nature of the fragmentary ions. The results of a comparison of the MD spectra with the structures of the molecules have confirmed the hypothesis expressed previously concerning the 7,8-MDOG as the center of localization of the charge, competing with the nitrogen atom and facilitating the elimination of various substituents from the diterpene skeleton. A comparison has been made of two methods of evaluating the common nature of the fragmentation reaction: from the energies of the metastable transitions and from the relative intensities of the metastable peaks. The two methods give mutually supplementary information concerning the nature of the fragmentation processes.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 397–407, May–June, 1987.     

Investigation of nonlinear dynamical properties by the observed complex behaviour as a basis for construction of dynamical models of atmospheric photochemical systems

The importance of the investigation of nonlinear dynamical properties (NDPs) of the atmospheric photochemical systems (PCSs) was demonstrated in ref. 1 and 2 (A. M. Feigin and I. B. Konovalov, J. Geophys. Res., 1996, 101 (D20), 26038; 1. B. Konovalov, A. M. Feigin and A. Y. Mukhina, J. Geophys. Res., 1999, 104 (D3), 3669). The only known way to study NDPs of any natural dynamical system (including atmospheric PCSs) is to construct a mathematical model of the system. The key point here is adequacy of the NDPs of the constructed model to the system observed. We propose a new approach to construction of such an adequate model for systems manifesting nonstationary chaotic behaviour and describe an algorithm based exclusively on nonlinear dynamical analysis of the observed time series (TS) without invoking any a priori knowledge about the properties of the system observed. Potentialities of the algorithm are demonstrated with the aid of a computer model of the mesospheric PCS. The duration of the "observed" TS is limited so that the system demonstrates only one--chaotic--type of behaviour, without any bifurcations throughout the observed TS. The proposed algorithm enabled us to make a correct prognosis of bifurcation sequences and calculate probabilities to reveal, at the time instant of interest, predicted regimes of the system's behaviour for times much greater than the length of the initial TS.     

Transient Changes in Topology and Energy on Extension of Polybutadiene Networks

The theory of elasticity of polymer networks has been developed along two lines. The phenomenological approach leads to the Mooney-Rivlin relation between stress and extension ratio for uniaxial extension. The statistical theory of elasticity, based on a model for polymer molecules, predicts a similar relation with one of the constants zero. Actual elastic properties of rubbers do not agree fully with either theory.

Experimental results are reported obtained with quantitatively cured polybutadiene and polyisoprene vulcanizates. These data are near-equilibrium results through the use of a cyclic stress sequence which largely eliminates the influence of long-time creep. The dependence of the initial modulus and the parameters of the Mooney-Rivlin relation on the chemical nature and the degree of branching of the polymer, the type of cross-links, and temperature has been investigated. A possible relation between the energy component of the elastic force and one of the parameters is discussed.

These results as well as those in the literature refer to irreversible processes. It is proposed that this irreversibility results from friction accompanying slippage of chain entanglements. This mechanism is compatible with the observed dependences. It is concluded that the variation of elastic properties with elongation is due to changes in network topography.

Some observations are made on the topological changes of vulcanizate networks at very high elongations. Similarities are pointed out between reinforcement by stress crystallization and by addition of carbon black. The effect of blacks is attributed mainly to preferential adsorption on the carbon particles of short network chains which become overstressed at high deformation. On adsorption the kinetic energy of these particular chains will be dissipated in the form of heat of adsorption.

Examples are given of the applicability of F. Bueche's relation between extension of the sample and that of the elastomer matrix in a filled vulcanizate. This equation differs from that based on Einstein's relation for the viscosity of suspensions, which has been shown to be applicable in other filled rubbers. The difference between the two relations may be associated with the absence or presence of chemical bonding of elastomer to filler.

Network topography has an influence on the ultimate properties of vulcanizates. Polybutadiene samples in which the cross-links are single bonds break at lower elongation than those with equal concentrations of cross-links consisting of 18-atom chains.     

The mass spectrometry of the products of the alkaline isomerization of diffugenin

Summary The features of the mass-spectrometric behavior of the products of the alkaline isomerization of diffugenin confirm the conclusions drawn previously concerning the structures and relative stabilities of these compounds.Deceased.Order of the Red Banner of Labor Institute of the Chemistry of Plant Substances of the Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 301–304, May–June, 1971.