高效液相色谱和高效液相色谱－质谱法测定粮食中互隔交链孢霉醇、互隔交链孢霉醇单甲醚及玉米赤霉烯酮

建立了粮食中互隔交链孢霉醇（ＡＯＨ）、互隔交链孢霉醇单甲醚（ＡＭＥ）和玉米赤霉烯酮（ＺＥＡ）三个毒素的ＨＰＬＣ定性定量分析法和粒子束ＬＣ－ＭＳ／ＥＩ￣＋鉴定方法。采用反相色谱,以８０％的甲醇水溶液作流动相,这三个毒素在Ｃ＿（１８）色谱柱上彼此间均获得较好的分离。方法对粮食中ＡＯＨ,ＡＭＥ两个毒素的回收率均在７９％以上。ＡＯＨ,ＡＭＥ两个毒素的最低检出限为１×１０￣（－９）ｇ。用所建方法对１００多个大骨节病病区、非病区的粮食样品进行了检测,结果为阴性。     

2,2,2-三氟-1-(9-蒽基)乙醇对映体在涂敷型手性固定相上的拆分

用高效液相色谱法在涂敷１５％（Ｗｔ）三苯基氨基甲酸纤维素醌手性柱上,考察了洗脱液正己烷／醇（Ｖ／Ｖ）中醇对分离－２,２,２－三氟－１（９－蒽基）乙醇对映体的影响,初步认为,在对映体分离过程中,洗脱液中醇与手性固定相的ＮＨ和Ｃ＝Ｏ形成氢键作用,此过程与对映体和手性固定相的ＮＨ和Ｃ＝Ｏ所形成氢键作用相竞争;洗脱液中醇的结构不同之所以影响对映体的分离效果,还与洗脱中醇改变固定相中手性空穴的立体环境有关,     

水相中金属铜表面生成亚铜—邻菲罗啉配合物的反应

本文研究了零价铜在邻菲罗啉水溶液中的反应。当溶液敞露于空气并存在有机阴离子Ｘ－时，例如苯甲酸盐（Ｂｚ）、对甲基苯磺酸盐（Ｔｓ）等，铜的表面生成了致密的反应产物的薄层，经ＩＲ、ＵＶ／ＶＩＳ、ＭＳ和元素分析证明了该薄层为相当纯的亚铜的邻菲罗啉配位化合物，结构为［Ｃｕ（ｐｈｅｎ）２］＋Ｘ－。在乙醇／甲苯混合溶剂中得到了表面反应产物的晶体［Ｃｕ（ｐｈｅｎ）２］（ＣＨ３Ｃ４Ｈ６ＳＯ３）Ｃ２Ｈ５ＯＨ，并用Ｘ－ｒａｙ测得了结构。本工作表明溶液中的ＣｕⅡ离子抑制Ｃｕ０氧化成ＣｕⅠ而影响反应层的形成，同时又促进ＣｕⅠ氧化成ＣｕⅡ的过程     

（R）—N—乙酰四氢噻唑—2—硫酮—4—羧酸与醇的反应

（Ｒ）－Ｎ－乙酰四氢噻唑－２－硫酮－４－羧酸与醇反应，在ＳＯＣｌ２存在下得到乙酸酯及四氢噻唑－２－硫酮－４－羧酸酯；在碳酸钾存在下得到乙酸酯及四氢噻唑－２－硫酮－４－羧酸；在二环己基碳二亚胺（ＤＣＣ）存在下得到缩水产物Ｎ－乙酰四氢噻唑－２－硫酮－４－羧酸酯。     

低碳醇合成Raney Cu－Co催化剂的研究Ⅰ．反应性能考察

本文在５６３Ｋ、６ＭＰａ及Ｈ＿２／ＣＯ＝２的条件下，考察了Ｃｕ／Ｃｏ比不同的几个ＲａｎｅｙＣｕ－Ｃｏ催化剂的反应性能。结果表明：ＲａｎｅｙＣｕ－Ｃｏ催化剂上ＣＯ加氢产物主要为Ｃ＿１－Ｃ＿６正构醇及Ｃ＿１－Ｃ＿８正构烃。烃和醇产品的分布均符合Ｓｃｈｕｌｚ－Ｆｌｏｒｙ方程。但醇产品的链增长几率（０．３－０．５５）均小于烃产品的值（０．６－０．７５）。Ｃｕ／Ｃｏ比不同的催化剂在进入活性稳定区之前，均经过了一个不尽相同的活性波动区，活性趋于稳定所需时间随Ｃｕ／Ｃｏ比增大而缩短。Ｃｕ／Ｃｏ＝０．３－１．５（原子比）时，就醇收率而言，ＲａｎｅｙＣｕ－Ｃｏ催化剂明显高于共沉淀Ｃｕ－Ｃｏ催化剂，Ｃｕ／Ｃｏ＝０．８（原子比）时，稳定醇收率达０．５７ｇ·ｇ￣（－１）·ｈ￣（－１）。     

薄层色谱法同时测定邻苯二酚、间苯二酚和对苯二酚异构体

研究了在自制硅胶薄板上邻苯二酚,间苯二酚异构体的薄层色谱特性。展开剂为本：乙醚：冰醋酸＝７：２：１（Ｖ／Ｖ／Ｖ）,Ｒｆ值分别为０．５９,０．５３,０．４８。检测限分别为１．０７×１０＾－４,１．６４×１０＾－４,１．９０×１０＾４ｍｏｌ／Ｌ。其他常见酚不干扰测定。可应用于实际样品的测定,回收率为９６％－１０４％。     

卡宾与醚C—H键插入反应的理论研究（Ⅲ）：CX（X=H,F,Cl）与甲乙醚C—H键插入反

用量子化学从头计算方法在ＭＰ２／６－３１Ｇ（ｇ）水平上研究了ＣＸ２（Ｘ＝Ｈ，Ｆ，Ｃｌ）与甲乙醚的Ｃ－Ｈ键插入反应，在甲乙醚的３个不同的Ｃ－Ｈ键（即甲基中ａ′－Ｃ－Ｈ键，乙基中ａ－Ｃ－Ｈ键和β－Ｃ－Ｈ键）上，反应势垒分别为１２３．８，３２．５，１５７．３ｋＪ／ｍｏｌ（Ｘ＝Ｃｌ）和２５４．３，１３０．０．３０４．２ｋＪ／ｍｏｌ（Ｘ＝Ｆ）。亚甲基与毗邻氧原子的各Ｃ－Ｈ键插入反应没有势垒，与乙基中β－Ｃ－Ｈ键插入势垒仅３．４ｋＪ／ｍｏｌ．甲乙醚中乙基α－Ｃ上的Ｃ－Ｈ键最有利于ＣＸ２的插入，甲基上的Ｃ－Ｈ键次之，乙基β－Ｃ上的又次之。     

CoTPP电化学催化原溴代环己烷的机理

以电化学循环伏安、现场ＥＳＲ电化学以及现场薄层电化学方法研究了电生Ｃｏ（Ｉ）ＴＰＰ与溴代五己烷的反机制。在ＤＭＦ中，Ｃｏ（Ⅱ）／Ｃｏ（Ⅰ）的氧化还原有明显的催化溴代环己烷还原的特片，反现场有自由基生成，反应产物之一是Ｃｏ－Ｃ键化合物，可以在１．３０Ｖ（ＳＣＥ）－电子还原，当存在ＣＨ２－ＣＨＣＮ时，。生成另一种Ｃｏ－Ｃ键化合物，该化合物在－１．１０Ｖ（ＳＣＥ）处一电子还原，证明溴代环己烷与Ｃｏ（Ｉ）     

薄层分离-库仑滴定法测定茄尼醇

提出以２ｍｏｌ／ＬＫＢｒ－醋酸（１：３Ｖ／Ｖ）为电液,在阳极电生溴与尼醇发生反应来测定茄尼醇含量的库仑滴定法。茄尼醇与溴反应,其ｎ值为１８,对于烟叶以物中茄尼醇,以正己烷－二氯乙烷－丙醇为展开剂,用薄层色地邓以分离,用库仑滴定法进行测定 。     

4—（6—甲基—2—苯并噻唑偶氮）间苯三酚反相高效液相色谱分离测定钒钴镍铬

作以新研制的４－（６－甲基－２－苯并噻唑偶氮）间苯三酚为柱前衍生试剂，用含１０ｍｍｏｌ／Ｌ的ｐＨ６．８０的ＨＡｃ－ＮａＡｃ缓冲溶液，１０ｍｍｏｌ／Ｌ ＴＢＡ．Ｂｒ和１×１０＾－４ｍｏｌ／ＬＥＤＴＡ的甲醇－水溶液（７８：２２，Ｖ／Ｖ）作流动相，在Ｃ１８柱上，１１ｍｉｎ内反相ＨＰＬＣ分离测定了Ｃｒ（Ⅵ），Ｖ（Ⅴ），Ｃｏ（Ⅱ），Ｎｉ（Ⅱ）。当Ｓ／Ｎ＝３时，其检出限分别是Ｖ（Ⅴ）５．４５ｎｇ，Ｃｏ（Ⅱ）     

N-二氯乙酰基噁唑烷合成反应的薄层色谱法研究

 用薄层色谱法监测了用二氯乙酰氯、醇胺和酮合成的除草剂的安全剂N 二氯乙酰基 口恶唑烷的反应过程。方法操作简便、快速、准确。     

重楼中薯蓣皂甙元的反相高效液相色谱测定

采用高效液相色谱法测定了重楼中薯蓣皂甙元的质量分数。样品先经甲醇提取,再经酸水解,将重楼甾体皂甙转变成薯蓣皂甙元,以ＳｙｍｍｅｔｒｙＣ８柱为色谱柱,以Ｖ（乙腈）∶Ｖ（水）＝７５∶２５溶液为流动相,检测波长２０３ｎｍ,重复性较好,结果令人满意。     

Effect of a thin spreading solvent film on the efficiency of the hexadecan-1-ol monolayer deposited for water evaporation retardation

The influence of a thin spreading solvent film (ethanol, diethyl ether, and three fractions of petroleum ether boiling at 30–60 °C, 60–90 °C, and 90–120 °C) on the properties of hexadecan-1-ol (C₁₆H₃₃OH) monolayers at the air—water interface was studied. The specific evaporation resistance and the surface pressure were determined to describe the spreading behavior of the C₁₆H₃₃OH monolayers. The physical properties of the solvents and the images obtained in an atomic force microscope were examined. The time of establishing the equilibrium spreading surface pressure of monolayers can be reduced using a more volatile solvent with a lower boiling point and a lower relative density. The influence of the monolayer nature on water evaporation corresponds to the order of changing the solvent spreading rate: petroleum ether (30–60 °C) > diethyl ether > ethanol > petroleum ether (60–90 °C) > petroleum ether (90–120 °C). The monolayers formed upon petroleum ether (30–60 °C) spreading form a film with a less deficient and relatively planar surface. When ethanol is used as a spreading solvent, water evaporation is accelerated rather than retarded, while petroleum ether (30–60 °C) is more appropriate for this purpose.     

Thin-layer chromatography of chlorinated anisoles and veratroles

Summary The thin-layer chromatography of chlorinated anisoles (methoxybenzenes) and veratroles (1,2-dimethoxybenzenes) has been examined on silica gel G60 and RP-18 thin-layer plates. More than fifty solvent systems were screened and some of them recommended for particular separations. Acetone was shown to be suitable for group separation of both chlorinated anisoles and veratroles on a silica gel G60 stationary phase having a very narrow range of R_F values. On the other hand, benzene, dichloromethane and the various mixtures of light petroleum (b.p. 40–60°C) and a more polar eluent (such as diethyl ether, acetone or ethyl acetate) were recommended for separation of certain individual isomers. The best separation of chloroanisoles was achieved using RP-18 plates and methanol-water (9010) as the solvent system.     

Decay time distribution analysis of Yt-base in benzene-methanol mixtures

Frequency-domain fluorometry was used to measure intensity decays of synthetic Yt-base in mixtures of benzene-methanol at 20 degrees C. Multiexponential analysis shows that the decay of Yt-base fluorescence in benzene and methanol can be well fitted to a single-exponential model with tau = 9.67 ns and 6.25 ns respectively. In mixtures of benzene-methanol the decays became heterogeneous, and the maximum of heterogeneity observed was in a mixture containing 6% methanol. Since we expected a distribution of Yt-base solvation states in the solvent mixtures, and because the decay times of Yt-base are sensitive to solvent, we analyzed the data in terms of decay time distributions. The goodness-of-fit for the unimodal distribution model which has two floating parameters was equivalent to that found using the double exponential model with three floating parameters. The Lorentzian distribution model appears to provide a slightly superior fit relative to the Gaussian distribution model. These results suggest that the intensity decays of solvent-sensitive fluorophores in mixed solvents are described by a distribution of decay times.     

An effective high-speed countercurrent chromatographic method for preparative isolation and purification of mollugin directly from the ethanol extract of the Chinese medicinal plant Rubia cordifolia

The medicinal plant Rubia cordifolia has been used widely in traditional Chinese medicine (TCM) for its antibacterial, antioxidant and anti-inflammatory activities. In this study, a preparative high-speed countercurrent chromatography (HSCCC) method for isolation and purification of the bioactive component mollugin directly from the ethanol extract of R. cordifolia was successfully established by using light petroleum (bp 60-90 degrees C)/ethanol/diethyl ether/water as the two-phase solvent system. The upper phase of light petroleum/ethanol/diethyl ether/water (5:4:3:1 v/v) was used as the stationary phase of HSCCC. Under the optimum conditions, 46 mg of mollugin at 98.5% purity, as determined by HPLC, could be yielded from 500 mg of the crude extract in a single HSCCC separation. The peak fraction of HSCCC was identified by 1H NMR and 13C NMR.     

Emergency toxicological screening for drugs commonly taken in overdose

A procedure is described for the screening of body fluids for the presence of drugs commonly involved in poisonings. Separate acidic and basic extracts of the specimen are made with chloroform, followed by concentration and thin-layer chromatography of the two extracts. Identification is based on R_F values, colours produced by spray reagents and spot patterns formed by the drug and its metabolites. Six simple colour tests are carried out concurrently with the preparation of these extracts. When examining urine for the presence of benzodiazepines a separate procedure involving hydrolysis, petroleum ether extraction and subsequent thin-layer chromatography is performed.     

Quality evaluation and quantification of cucurbitacin E in different cultivars of Cucumis sativus L. fruit by a validated high-performance thin-layer chromatography method

Cucumis sativus L. of the Cucurbitaceae family, commonly known as cucumber, is commercially cultivated worldwide. The major phytoconstituents present in the Cucurbitaceae family are different curcurbitacins, principally cucurbitacin E. The content of cucurbitacin E differs within the species or cultivars due to factors like genetic variation and geographical location. The present study reports a simple and rapid quantitative analysis of cucurbitacin E in 5 different C. sativus cultivars by a validated high-performance thin-layer chromatography (HPTLC) method. The mobile phase contained petroleum ether, ethyl acetate and formic acid in the ratio of 40:60:0.5 (V/V). Cucurbitacin E was analyzed densitometrically and the absorbance wavelength was 254 nm. The method showed R_F spot = 0.79 ± 0.06, corresponding to cucurbitacin E in various samples. The calibration curve of standard cucurbitacin E showed good linear relationship in the concentration range of 2‒10 µg/spot with a correlation coefficient (r) > 0.99. The HPTLC method was validated in terms of sensitivity, linearity, accuracy, precision, and specificity as per the International Conference on Harmonization (ICH) guidelines. The present study revealed that the content of cucurbitacin E differs among the C. sativus cultivars. This method may be beneficial for addressing the quality-related aspects of C. sativus for food and pharmaceutical preparation.

     

高效液相色谱法同时测定牛肉及其制品中敌草隆、绿麦隆的残留量

介绍了用高效液相色谱同时测定牛肉及其制品中脲类除草剂——敌草隆、绿麦隆残留量的方法。色谱柱为ＳｅｌｅｃｔｏｓｉｌＣ１８柱,流动相为甲醇－水（６０∶４０,Ｖ／Ｖ）,ＵＶ－２４５ｎｍ检测。最小检测量：敌草隆为０．４ｎｇ,绿麦隆为０．５ｎｇ。线性范围均为０．０５～１０ｍｇ／Ｌ。回收率：敌草隆为８７．３４％～８７．６４％,绿麦隆为８８．７８％～９１．９４％。     

Optimization of pressurized liquid extraction of Piper gaudichaudianum Kunth leaves

Piperaceae family is original from tropical regions and it shows more than 700 species around the world. Piper gaudichaudianum Kunth is the specie more abundant in Brazil, occurring from Northeast to South Brazil. In this paper, it was investigated the influence of some experimental parameters on the pressurized liquid extraction (PLE) of P. gaudichaudianum Kunth leaves, using petroleum ether as extractor solvent. The optimization of the main variables involved in the PLE process (extraction temperature and time) has been done by response surface methodology (RSM) using, as responses, the extraction yield and the chromatographic profile (GC/MS) of the extracts. The optimized procedure employed 3 g of ground leaves, 10 min of extraction and one cycle of extraction at 85 degrees C. The major compounds present in the petroleum ether extracts were: palmitic acid, stearic acid and nerolidol. The results presented in this work show the possibility of using a fast and easy process to recover compounds from P. gaudichaudianum Kunth.