含硅路易斯酸的发展及其在有机合成中的应用

综述了含硅路易斯酸R₃SiX [X＝I, OTf, NTf₂, C(C₆F₅)Tf₂等]和(R₃SiX＋ML_n)的发展、合成以及它们在有机合成中的应用. 它们主要被用来催化Aldol, 烯丙基化, Diels-Alder, Ene和Friedel-Crafts等反应. 催化剂的用量一般为0.5～20 mol%, 并随着催化剂的活性不同, 反应产率从一般到良好不等. 催化剂活性顺序为R₃SiNTf₂＞R₃SiOTf, (R₃SiX＋ML_n)＞R₃SiX. 也对近年出现的手性含硅路易斯酸的发展和应用进行了概述, 当手性双-(多氟甲磺酰)-亚胺基硅烷用于催化环戊二烯和丙烯酸甲酯的Diels-Alder反应时, ee值高达54%.     

毛细管区带电泳法快速测定复方布洛芬片的有效成分

研究了用毛细管区带电泳法快速测定复方布洛芬片中布洛芬和伪麻黄碱含量的方法。在０．０２５ｍｏｌ／Ｌ的磷酸盐缓冲液（ｐＨ８．１）中，上述两组分可在３ｍｉｎ内得以完全分离，用紫外检测器在２１０ｎｍ处检测，并以外标法定量。１１次测定含有９．５ｍｇ／Ｌ盐酸伪麻黄碱和６６．７ｍｇ／Ｌ布洛芬的试样溶液，相对标准偏差为２．９％（伪麻黄碱）和１．９％（布洛芬），回收率为１０３．１％（伪麻黄碱）和９７．６％（布洛芬）。应用毛细管区带电泳法测定复方布洛芬片剂的含量，所得结果与ＨＰＬＣ法一致。     

Capillary electrophoresis: An integrated system with a unique split-flow sample introduction mechanism

The performance of an integrated capillary electrophoresis system with a novel split-flow sample injection mechanism and special high sensitivity UV absorbance detector is described. Sample introduction into the capillary is accomplished with a standard HPLC-type microliter syringe. The injected sample is divided proportionally between the separation capillary and an adjustable splitvent. The volume of sample introduced into the capillary can be manipulated by varying the length or the i.d. of the splitvent tubing; or the volume of sample injected. Data are presented showing reproducibility of retention time, peak height, and peak area; minimum detectability; and operation at short UV wavelengths.     

JEE—4x型真空镀膜仪功能扩展

报道了对ＪＥＥ－４ｘ型真空镀膜仪蒸发装置的改进以及建立蒸发材料回收装置的具体方法，并介绍了改进后该仪器在高分辨扫描电镜样品制备上的应用实例．实验证明，上述改进不但扩展了ＪＥＥ—４ｘ型真空镀膜仪的制样功能又节省了蒸发材料，集中了离子溅射法及常规高真空镀膜法的优点，完全满足ＳＥＭ样品的分析要求，该方法简单易操作．     

Poly(methacrylic acid-ethylene glycol dimethacrylate) monolith in-tube solid-phase microextraction applied to simultaneous analysis of some amphetamine derivatives in urine by capillary zone electrophoresis

A method based on in-tube solid-phase microextraction and capillary zone electrophoresis (CZE) was proposed for simultaneously determining four amphetamines (amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, and 3,4-methylenedioxymethamphetamine) in urine. A poly(methacrylic acid-ethylene glycol dimethacrylate) monolithic capillary column, which can provide sufficient extraction efficiency, was introduced for the extraction of amphetamines from urine samples. The hydrophobic main chains and acidic pendant groups of the monolithic column make it a superior material for extraction of basic analytes from aqueous matrix. After extraction, the samples were analyzed by CZE. The best separation was achieved using a buffer composed of 0.1 M disodium hydrogen phosphate (adjusted to pH 4.5 with 1 M hydrochloric acid) and 20% methanol v/v, with a temperature and voltage of 25 degrees C and 20 kV, respectively. By applying electrokinetic injection with field-amplified sample stacking, detection limits of 25-34 microg/L were achieved. Excellent method of reproducibility was found over a linear range of 0.1-5 mg/L. Determination of these analytes from abusers' urine sample was also demonstrated.     

Retrieving definitional content for ontology development

Ontology construction requires an understanding of the meaning and usage of its encoded concepts. While definitions found in dictionaries or glossaries may be adequate for many concepts, the actual usage in expert writing could be a better source of information for many others. The goal of this paper is to describe an automated procedure for finding definitional content in expert writing. The approach uses machine learning on phrasal features to learn when sentences in a book contain definitional content, as determined by their similarity to glossary definitions provided in the same book. The end result is not a concise definition of a given concept, but for each sentence, a predicted probability that it contains information relevant to a definition. The approach is evaluated automatically for terms with explicit definitions, and manually for terms with no available definition.     

手性氨基酚配体及其衍生物在不对称催化中的应用

综述了手性氨基酚配体及其衍生物的研究进展, 着重介绍其在不对称催化烷基化、烯基化、Michael加成、aldol反应及环丙化等反应中的应用.     

Determination of terbinafine in pharmaceuticals and dialyzates by capillary electrophoresis

A capillary electrophoresis method has been developed for the separation and determination of terbinafine (TER) in various pharmaceutically relevant matrices. Capillary zone electrophoresis (CZE) separation and UV absorbance photometric detection were carried out in a 160 mm capillary tube with a 300 μm i.d., hydrodynamically (membrane) closed. The influences of pH, carrier cation and counterion on migration parameters of TER were studied and the following conditions were selected: a 20 mmol l⁻¹ glycine running buffer adjusted to pH 2.7 with acetic acid, 0.2% (w/v) methylhydroxyethylcellulose (m-HEC) as an electro-osmotic flow (EOF) suppressor, a 250 μA driving current, and 20 °C. The optimized separation conditions were convenient for the determination of TER in commercial tablets and spray and in dialyzates. Here, the dialysis was used to investigate in vitro permeation of TER through the skin from the gel. The samples of dialyzates were examined with and without simple extraction procedure and the results were compared. A permeation profile of the drug present in the gel of given composition was obtained analyzing pretreated samples. The proposed electrophoretic method was successfully validated. It was suitable for the simple, sensitive, rapid and highly reproducible assay of TER. CZE analysis was completed within 5.5 min. The detection limit of TER was 1.73 μmol l⁻¹ at a 224 nm detection wavelength. The intra- and inter-laboratory precisions over the concentration range 6.0-60.0 μmol l⁻¹ were between 0.32-0.69% and 1.04-1.44% including R.S.D. of migration times and peak areas, respectively. The mean absolute recoveries of drugs from samples were found to be 98.34 (tablets) and 99.47% (spray). It is suggested that there are potentialities to determine TER present in unpretreated complex samples, as CZE in a hydrodynamically closed separation system may be easily on-line combinable with purification and preconcentration CE modes (e.g., isotachophoresis, ITP).     

银络合物在催化核上的还原反应

研究了尿嘧啶银络合物在胶态金属及其硫化物核上被对苯二酚还原的反应，并以Ａｇ和Ｐｔ电极代替催化核与对苯二酚显影剂和银络合物组成原电池作为电化学模型，分别测定该络合物阴极反应和对苯二酚阳极反应的电流。结果表明，原电池的电流大小与反应速度成正比关系，从而为物理显影电极理论提供实验依据。     

Determination of imazalil by on-line coupled capillary isotachophoresis with capillary zone electrophoresis

A simple, rapid and reproducible capillary isotachophoretic on-line coupled with capillary zone electrophoresis (CITP-CZE) method for the determination of IMz in food packaging extracts and its residues in apples is described. A good separation of the IMZ from other sample constituents was achieved within 15 minutes without any sample clean up. Method characteristics (linearity, accuracy, intra-assay and detection limit) were determined. Less amount of time involved, sufficient sensitivity and low running cost are the important attributes of CITP-CZE method.