长光路光度法测定中药材中痕量硒

本文研究了用长光路光度法测定痕量硒。在酸性溶液中，Ｓｅ（Ⅳ）催化ＫＣｌＯ３氧化苯肼成偶氮离子，继而与变色酸生成红色偶氮化合物。硒含量在１．０×１０－９～２．０×１０－７ｇ／ｍＬ范围内遵守比尔定律。巯基棉分离后，测定中药材中总硒，获得满意结果。     

Synthesis of monodisperse poly(chloromethylstyrene-co-divinylbenzene) beads and their application in separation of biopolymers

The monodisperse, porous poly(chloromethylstyrene-co-divinylbenzene) beads of 7.9 microm were prepared by a single-step swelling and polymerization method. The seed particles prepared by dispersion polymerization exhibited good absorption of the monomer phase. Based on this media, a weak cation-exchange (WCX) stationary phase for HPLC was synthesized by a new chemically modified method. The prepared resin has advantages of biopolymer separation, high column efficiency, low column backpressure, high protein mass recovery, and good resolution for proteins. The dynamic protein-loading capacity of the synthesized WCX packings was 18.2 mg/g. Five proteins were separated in 3.0 min using the synthesized WCX stationary phase. The experimental results show that the obtained WCX resin has very weak hydrophobicity. The WCX resin was also used for the rapid separation and purification of lysozyme from egg white in 5.0 min with only one step. The purity and specific bioactivity of the purified lysozyme were found to be more than 93% and 70 245 U/mg, respectively.     

Extending the scope of enantiomer separation by capillary supercritical fluid chromatography on immobilized polysiloxane-anchored permethyl-β-cyclodextrin (Chirasil-Dex)

Immobilized polysiloxane-anchored permethyl-β-cyclodextrin (Chirasil-Dex) with a cyclodextrin content of approximately 30 % by weight, previously employed as a versatile chiral stationary phase for the separation of enantiomers by GC, has been used for the separation of enantiomers by capillary supercritical fluid chromatography (SFC). A considerable number of racemates could be resolved, e.g. aromatic alcohols, amino alcohols (TFA derivatives), and underivatized acids. Many pharmaceutical compounds were among those analyzed, including several NSAIDs (e.g. ibuprofen and ketoprofen), a steroidal drug (nor-gestrel), a barbiturate (hexobarbital), and others. Among the racemates resolved were many which cannot be analyzed by GC owing to low volatility or decomposition at elevated temperatures. For two racemates, analysis temperature and mobile phase density were systematically varied to give constant analysis times or capacity factors k. Low temperatures (ca 60 °C) yielded the best separation in term of separation factor, α, or resolution, R_s, even though higher densities had to be used. In comparison with GC, capillary SFC was able to furnish higher separation factors and similar resolution. The applicability of capillary SFC for the analysis of mixtures of cyclodextrin derivatives, e.g. those used in the synthesis of Chirasil-Dex, was, furthermore, demonstrated.     

Analysis of preservatives in cosmetics—Methylisothiazolones

Summary Antimicrobially active formulations based on 2-methyl-3(2H)-isothiazolone and 5-chloro-2-methyl-3(2H)-isothiazolone (Kathon CG, Euxyl K 100) are incorporated into manufactured cosmetics as preservatives. In this paper we report on the analysis of these active components by means of liquid chromatography. It is conventional for the original methylisothiazolone components in cosmetics to be analyzed by reversed phase high-performance liquid chromatography after column chromatographic separation and flash chromatographic purification. In our new analytical method the methylisothiazolones are converted into the respective -thiosubstituted acrylamide derivatives, which are ionic substances, with the help of the nucleophilic reagent hydrogensulfite. An ion pair high-performance liquid chromatographic method has been developed for the separation and quantification of these derivatives.     

亲和标记-基质辅助激光解吸电离飞行时间质谱用于蛋白质相对定量方法的研究

将亲和标记技术和基质辅助激光解吸电离飞行时间串联质谱联用,建立了蛋白质相对定量方法,以牛血清白蛋白为实验对象,考察了该方法的准确度、重现性等指标;又以数种标准蛋白混合物为研究对象,考察了该方法的动态范围及相应的标准偏差,为实际生物样品中差异蛋白质分析奠定了基础。     

Separation of Anions of Organic Acids in Concentrated Solutions by Means of Capillary Isotachophoresis

The separation of a mixture containing anions of nine organic acids is investigated on an instrument for capillary isotachophoresis with an optical detector for the registration of boundaries. The separation is conducted in concentrated solutions of sodium salts. A counterflow is used during the separation.     

毛细管电泳法快速分离和检测肠毒性大肠杆菌

 建立了快速分离和检测引起仔猪腹泻的肠毒性大肠杆菌K88、K99和 987P细菌细胞的毛细管区带电泳方法 ,并进行了腹泻仔猪粪便中肠毒性大肠杆菌的应用检测分析。结果表明 ,在电泳缓冲液为 0 0 5mol/LNa2 CO3 NaHCO3(pH 9 9)、分离电压为 1 4 1kV、检测波长为 2 1 0nm的电泳条件下 ,E coliK88、K99和 987P的细胞分别具有单一、稳定的特征谱峰 ,其保留时间的相对标准偏差RSD≤ 0 9% ;在确定的实验条件下 ,实现了腹泻仔猪粪便中肠毒性大肠杆菌的快速检测分析 ,发现将出生 5d～ 6d的腹泻仔猪粪便引入培养基中增殖后主要检出K88。     

离子色谱法同时测定水中六种阳离子

研究了用抑制电导离子色谱法一次进样同时测定水中Li^ ,Na^ , NH4^ ,Mg^2 ,Ca^2 的色谱法条件，相对标准偏差小于0．5％，加标回收率在97．5％－104．0％。在水质分析中运用t检验法，比较了用钙、镁离子浓度计算和传统方法测定的总硬度之间是否存在显著性差异。     

Concentration and clean-up of trace hydrocarbons from atmospheric particulate matter

Summary The aim of this work is to establish the best conditions for concentration and purification steps in the trace analysis of aliphatic and polycyclic aromatic hydrocarbons (PAH) from atmospheric particulate matter by gas chromatography-flame ionisation detection (GC-FID) and high performance liquid chromatography with ultraviolet and fluorescence detection (HPLC-UV-FL). The best results for the more volatile compound were obtained with a combination of rotary evaporation and a stream of nitrogen (near to 100% for aliphatic hydrocarbons and from 70 to 105% for PAH). Two types of solid phase extraction (SPE)cartridges (Supelclean ^tm LC-Silica SPE tubes and Sep-Pak^? Plus silica cartridges) and glass column were examined for the purification and fractionation step. Blank chromatograms of both types of cartridges analysed by GC-FID made this study difficult, because a PSS (programmed split-splitless) injector was employed thereby increasing the sensitivity. This problem was not observed in the HPLC-UV-FL blank chromatograms of these cartridges. Glass columns filled with silica and alumina were chosen because no interference was found in the GC-FID blank chromatograms and the best recoveries in the fractionation of both aliphatic hydrocarbons and PAH were achieved. This is especially important when aliphatic hydrocarbons concentrations are lower than 1 μg mL⁻¹. Finally, the selected conditions were applied to the analysis of hydrocarbons in real atmospheric particulate samples.     

Enhanced chromatographic resolution of amine enantiomers as carbobenzyloxy derivatives in high-performance liquid chromatography and supercritical fluid chromatography

The carbobenzyloxy (cbz) protecting group is evaluated for it's potential to enhance the resolution of chiral amine enantiomers using high-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC). A series of cbz derivatives of commercially available racemates was prepared and analyzed by enantioselective chromatography using a variety of mobile phases and polysaccharide and Pirkle-type chiral stationary phases (CSPs). The cbz-derivatized product consistently demonstrated enhanced chiral resolution under HPLC and SFC conditions. Improved selectivity and resolution combined with an automated preparative HPLC or SFC system can lead to the rapid generation of highly purified enantiomers of desirable starting materials, intermediates or final products.