毛细管电泳安培检测扑热息痛及其水解物

研究了各种电化学预处理条件下碳纤维电极对扑热息痛及水解物的电化学行为。确定该体系最佳预处理条件为０．２Ｖ电位下阳极化１ｍｉｎ，再于－２．０Ｖ下阴极化１０ｓ。预处理后的碳纤维伏安响应得到明显提高。运用最佳条件并在支持电解中加入添加剂后，扑热息痛及其水解物在毛细管电泳上获得很好的分离和检测。其中扑热息痛的检测下限为２．７８ｐｇ；对氨基酚为１．８４ｐｇ。     

Spectroscopic characterization of effective components anthraquinones in Chinese medicinal herbs binding with serum albumins

The interactions of serum albumins such as human serum albumin (HSA) and bovine serum albumin (BSA) with emodin, rhein, aloe-emodin and aloin were assessed employing fluorescence quenching and absorption spectroscopic techniques. The results obtained revealed that there are relatively strong binding affinity for the four anthraquinones with HSA and BSA and the binding constants for the interactions of anthraquinones with HSA or BSA at 20 degrees C were obtained. Anthraquinone-albumin interactions were studied at different temperatures and in the presence of some metal ions. And the competition binding of anthraquinones with serum albumins was also discussed. The Stern-Volmer curves suggested that the quenching occurring in the reactions was the static quenching process. The binding distances and transfer efficiencies for each binding reactions were calculated according to the F?ster theory of non-radiation energy transfer. Using thermodynamic equations, the main action forces of these reactions were also obtained. The reasons of the different binding affinities for different anthraquinone-albumin reactions were probed from the point of view of molecular structures.     

冠醚型电极对局部麻醉药响应功能的研究

用二苯并24-冠-8作为活性物质、邻苯二甲酸二(2-乙基)己酯为增塑剂制得PVC膜电极。电极对局麻药丁卡因、普鲁卡因和利多卡因具有能斯特响应,用于局麻药针剂的测定取得满意的结果。     

偏最小二乘法分光光度同时测定复方扑热息痛片中各组分含量

本文介绍了偏最小二乘法(PLS)用于多组分分光光度分析的基本原理和算法.研究了复方扑热患痛片中扑热息痛、阿司匹林和咖啡因的PLS测定方法,各组分的平均回收率分别为99.88±0.33％、99.99±0.14％和99.92±1.24％(置信度95％).     

Amperometric detection of catecholamines with liquid chromatography at a novelly constructed prussian blue chemically modified electrode

A novel Prussian blue chemically modified electrode (CME) was constructed and characterized for liquid chromatography electrochemical detection (LCEC) of catecholamines. Both anodic and cathodic peaks could be obtained by monitoring at constant applied potential at anodic and slightly cathodic potential ranges (0.3-0.7 and -0.2-0.1 V vs. SCE), respectively. When arranged in a series configuration, using the modified electrodes as generating and collecting detectors, extremely high effective collection efficiencies of 0.91 (for norepinephrine) and 0.58 (for dihydroxyphenylacetic acid) were achieved in dual-electrode LCEC for catecholamines; and a linear response range over 3 orders of magnitude and a detection limit of 10 pg were obtained with a downstream CME as the indicating detector.     

A supported gold catalyst for the elimination of hydrogen from CO2 feed gas in the production of urea

Supported gold catalyst for eliminating hydrogen from CO₂ feed gas in the production of urea is found to be superior to other industrial catalysts (e.g. Pt/Al₂O₃ and PdPt/Al₂O₃) in catalytic activity and resistance to sulfur poisoning.     

Stereo- and enantioselective determination of pesticides in soil by using achiral and chiral liquid chromatography in combination with matrix solid-phase dispersion

The separation of enantiomers and diastereomers of 8 commonly used pesticides was investigated by liquid chromatography (LC) using a Chiralcel OD column (cellulose tris-3,5-dimethylphenylcarbamate as the chiral stationary phase) and a Pirkle-type Chirex 3020 column (urea derivative from the reaction of (R)-1-(alpha-naphthyl)ethylamine with (S)-tert-leucine, chemically bonded to 3-aminopropylsilanized silica as the chiral stationary phase). The pesticides studied included one organophosphorus insecticide (phenthoate), 3 triazole fungicides (uniconazole, diniconazole, and propiconazole), and 4 pyrethroids (fenpropathrin, beta-cypermethrin, beta-cyfluthrin, and alpha-fenvalerate). The enantiomers were separated within 20 min with a resolution of > or = 1.5 using a mixture of n-hexane and 2-propanol as the mobile phase for all the pesticides studied except propiconazole, for which only the 2 diastereomers were baseline separated. This method allows determination of the enantiomers or stereoisomers of the above pesticides in soil. The strategy was as follows: (1) First, the total concentration(s) of the enantiomer pair(s) of a chiral pesticide in soil was (were) determined by a newly developed matrix solid-phase dispersion (MSPD) procedure, followed by silica-based LC quantification. The recoveries ranged from 76.5 to 93.6% with relative standard deviations of 6.0%. (2) Second, the enantiomeric ratio(s) (ER(s)) of the chiral pesticide was (were) determined by LC with a chiral stationary phase after fractionation of the MSPD extract by silica-based LC. The determined ERs or stereoisomeric ratio(s) (SR(s); for propiconazole, only the SR of the 2 diastereomers was determined) in soil samples spiked with the above 8 racemic pesticides agreed with those of the corresponding standard solutions. (3) Third, based on the total concentrations and the corresponding ERs, the concentration of each enantiomer in soil was calculated. The proposed method is rapid, precise, and sensitive, and is appropriate for the investigation of the stereo- and enantioselective degradation of pesticides in environmental media.     

Conformations of fold part in isotactic polypropylene lamella with diamond lattice model

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Propane oxidation over Pd/LaFe0.8Co0.2O3 catalyst

Pd/LaFe_0.8Co_0.2O₃ was found to be more active than the Pd/Al₂O₃ catalyst in propane oxidation. Activity and the oxidation state of palladium were strongly affected by the redox ratio (S) of reactants. Higher propane conversion could be obtained under rich conditions at higher temperatures, contributing to steam reforming. The presence of excess steam would bring about inhibition and oscillation.