Headspace Solid-phase Microextraction–Gas Chromatographic–Mass Spectrometric Analysis of the Essential Oils of Two Traditional Chinese Medicines, Angelica pubescens and Angelica sinensis

Angelica pubescens and Angelica sinensis belong to the Umbelliferae family and both are used as traditional Chinese medicines. In the present study, headspace solid-phase microextraction (HS-SPME) with gas chromatography-mass spectrometry (GC-MS) was used for the analysis of the volatile constituents present in their roots. Eighty-seven compounds in Angelica pubescens and thirty-six compounds in Angelica sinensis were identified by GC-MS. Their relative contents were calculated by the peak area ratio. HS-SPME was compared to steam distillation (SD) by analyzing the volatile constituents of Angelica sinensis root. A good agreement between results obtained with both techniques was found. As a conclusion, HS-SPME is a powerful tool for determining the volatile constituents present in the TCMs.     

Synthesis of Some Allyl-β-Cyclodextrin Derivatives and their Properties as Capillary GC Stationary Phases

Summary Three -Cyclodextrin derivatives (-CDs) were synthesized by substituting the 2,6-OH groups of -CD with allyl groups and the 3-OH groups with three different acyl groups (valeryl, heptanonyl, octanoyl). The chromatographic properties of these -CDs as stationary phases for capillary gas chromatography (CGC) were studied. The test results showed that the three -CDs possessed good coating properties and that the capillary columns coated with them exhibited high column efficiency. These -CDs can separate not only the disubstituted benzene isomers but also some racemic compounds.     

Investigation of gas chromatographic interaction mechanism on permethylated cyclodextrins by molecular modelling

Summary The capillary gas chromatographic retention behavior of -pinene and tricyclene has been investigated on stationary phases of different polarities. On all but one of the columns employed, tricyclene eluted before -pinene; only permethylated -cyclodextrins dissolved in moderately polar polisiloxanes gave a reversed elution order. The intermolecular interactions which caused the unexpected retention behavior were investigated in detail, applying methods of computer simulation. To achieve this, we have developed a calculation algorithm on the basis of molecular mechanical optimizations and programmed it in a macro. This makes it possible to systematically investigate a given configuration space in which all the possible interactions can take place. It was shown that permethylated -cyclodextrin as host molecule for both guest molecules offers an optimum cavity size. As a result the number of energetically favorable contacts between host and guest molecules as well as the strength of the interactions in this stationary phase were larger. As a consequence the elution order, normally only influenced by the vapor pressure of the compounds at a given temperature, was changed. Nonspecific interactions played an especially important role for these kinds of substances.     

A study of the oxidation of vegetable oils by inverse gas chromatography

Summary Inverse gas chromatography is shown to be suitable for the study of the oxidation of vegetable oils. With air as carrier gas characteristic plots of retention index versus time are obtained for hydroxylic test solutes that are consistent with the oxidation behaviour of vegetable oils. Shifts of retention are found to be accompanied by changes of column efficiency due to the oxidative crosslinking of polyunsaturated vegetable oils. The technique also leads to useful information concerning the oxidation of antioxidant inhibited systems. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

Diagnostic and therapy-control of inborn metabolic disorders by high-performance liquid chromatography: 2,8-dihydroxyadeninuria,xanthinuria

Summary 2,8-Dihydroxyadeninuria and xanthinuria are inborn enzyme disorders which must be under lifelong therapeutic control. Quantitative determination of 2,8-DHA and xanthine using reversed phase HPLC was performed. A new application for the separation of purines shortens analysis-time. Examples of the determination of 2,8-DHA and xanthine before and under certain therapies are shown. Long term monitoring of the patients offers the possibility of a reliable prophylaxis against stone recurrence.     

人血清中地尔硫高效液相色谱法测定及药代动力学参数

建立了反相高效液相色谱法监测人口服地尔硫艹卓缓释片后血药浓度。血样用正己烷－氯仿－异丙醇混合溶剂（６０４０５）提取后，以Ｃ１８化学键合硅胶为固定相，甲醇－水－三乙胺为流动相，安定为内标，在２３９ｎｍ波长处定量检测。血药浓度在１５～３００μｇ／Ｌ范围内线性关系良好，最低检测浓度为３μｇ／Ｌ。批内（ｎ＝７）及批间（ｎ＝５）测定相对标准偏差分别小于６．８％和８．４％，回收率为９１％～１０４％。监测了８名健康人口服盐酸地尔硫艹卓缓释片后的不同时间的血药浓度变化，计算了有关的药代动力学参数。     

An application of the modified Poisson- Boltzmann equation in studies of osmotic properties of micellar solutions

The spherical cell model of colloidal solutions is applied in calculations of the osmotic pressure of micellar systems. The predictions of the nonlinear Poisson-Boltzmann equation (MPB) and of the Modified Poisson-Boltzmann equation (MPB) containing the leading terms of the fluctuation potential and the exclusion volume corrections to the mean potential acting on simple ions are compared with the results of recent computer simulations. Both PB and MPB seem satisfactory for solutions with monovalent counterions while the MPB is preferable for studies of the solutions containing divalent countenons.On leave from the University of Ljubljana, Ljubljana, Yugoslavia