毛细管气相色谱法测定中药中有机氯农药残留量

建立了江西省两种中药中有机氯农药残留量的气相色谱分析方法。样品以丙酮提取,在NaCl存在下,以正已烷进行液—液分配,提取液用H2SO4净化,采用DB—1701毛细管柱,GC—ECD检测有机氯农药残留量。最低检测限为1.0×10-3-5.0×10-3mg/kg,添加回收率为85.7%-115.2%,应用于实际样品中有机氯农药残留量的检测,获得了较为满意结果。     

X波段六腔渡越管振荡器的高频特性研究

 从麦克斯韦方程出发，采用时域有限差分法（FDTD）和离散傅里叶变换（DFFT）相结合的方法，通过数值计算得出了六腔开放式谐振腔中前四个谐振频率和场分布，计算出的谐振频率与实验测量结果基本相同。比较了开放腔和封闭腔谐振频率，验证了TEM波吸收边界条件，并在实际编程计算中得以应用。计算结果为六腔渡越管振荡器的机理研究提供了依据。     

A new cytotoxic limonoid from Odontadenia macrantha from the Suriname rainforest

Bioassay‐guided fractionation of the methanol extract of Odontadenia macrantha afforded a new limonoid, odontadenin A (1) and two known triterpenoids, lupeol (2) and α‐amyrin (3). The structure of 1 was established on the basis of 1D and 2D NMR and high‐resolution fast atom bombardment mass spectrometric data. The new compound was found to possess moderate cytotoxicity against A2780, the ovarian cancer cell line. Copyright © 2003 John Wiley & Sons, Ltd.     

Problem of the free oscillations of a capillary bridge

The free oscillations of a capillary bridge whose equilibrium shape is determined by the surface tension forces and the static gravity field are investigated. The values of 25 “lower” levels of the spectrum of natural oscillations of the capillary bridge are found for various control parameters in accordance with the experimental conditions.     

A method and program for mass quantum chemical calculations of protein—ligand docking complexes

A new fast computational method for mass calculations of docking complexes by the AM1/PM3 semiempirical methods is proposed. The computation time is shortened by at least an order of magnitude compared to alternative schemes of quantum chemical calculations. The root-mean-square deviation of the AM1 calculated energies of formation of complexes from the results obtained by conventional diagonalization procedure is at most 0.4 kcal mol⁻¹. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 418–420, February, 2008.     

Theoretical Description of the Third Order Parametric Wave Mixing in a Gas-Filled Capillary of Femto-Second Laser Pulse

The theoretical signal-pressure curves are calculated from approximate analytical solutions of the coupledequations describing the third order parametric wave mixing in a gas-filled capillary of femto-second laser pulses. Thecomparison with the corresponding experimental curves suggests that the following three factors exert important influ-ences on the degree of fitting between the theoretical and experimental results: the walk-off, the phase modulation, andthe third order harmonic of idler pulse.     

Gas chromatographic system equipped with a mass detector and a selective nitrogen-phosphorous detector operating simulataneously in the analysis of pesticide residues

The possibility to perform gas chromatographic analysis using both a mass detector and a selective nitrogen-phosphorous detector will enable highly sensitive analytical results and an optimal identification reliability. In this work we describe an easily workable technical solution, which has been accomplished in our laboratory and the application of the above system to analytical procedures for the detection and determination of nitrogenous herbicides in drinking water and phosphorylated pesticides in agricultural products is discussed.     

Non-aqueous capillary zone electrophoresis method for the analysis of paroxetine, tamoxifen, and their main metabolites in urine

The potential of non-aqueous capillary electrophoresis (NACE) was investigated for the simultaneous separation of paroxetine, tamoxifen, and their main metabolites. Baseline separation of the studied solutes was obtained on a  μm capillary using a non-aqueous buffer composed of 18 mM ammonium acetate and 1.1% acetic acid in 80:20 (v/v) methanol-acetonitrile, with a temperature and voltage of 22 °C and 15 kV, respectively. Clomipramine was used as internal standard. Aspects such as stability of the solutions, linearity, accuracy, precision and ruggedness were examined in order to validate the proposed method. Detection limits obtained for all the studied compounds ranged between 3.0 and 7.1 μg l⁻¹. The developed method is sensitive and robust and was used to determine paroxetine, tamoxifen, and their metabolites at clinically relevant levels in human urine. Before NACE determination, the samples were purified and enriched by means of an extraction-pre-concentration step with a pre-conditioned C₁₈ cartridge. Determination of these analytes in the urine of four females urines was demonstrated.     

Determination of Aroma Compounds in Blackberry by GC/MS Analysis

The aromatic composition of five blackberry cultivars (Bursa 2, Navaho, Nessy, Chester Thornless, and Jumbo) was studied. The Im-SPME (Immersion Solid Phase Micro Extraction) extraction technique was applied and the samples were analyzed by GC/MS. Furfural and its derivatives were found to be the major aromatic compounds and 5-hydroxymethylfurfural was the most abundant compound in all the blackberry varieties.     

Characterization of Saccharomyces Sp. through determination of amino acid profiles by capillary gas chromatography

The Saccharomyces strains uvarum, montuliensis, bayanus, capensis and florentinus were grown in liquid media prepared from a 1% aqueous glucose solution to which 0.05% of ammonium sulfate or urea were added as the only nitrogen supply. The amino acids exuded during incubation were isolated by cation exchange and derivatized as the corresponding N,O-heptafluorobutyryl isopropyl esters. Separation was achieved on a highly deactivated glass capillary column coated with OV-101. A characteristic amino acid profile was obtained for each of the species studied, allowing the construction of a chemotaxonomic tree, on the basis of present or absent acids.