色谱填料制备技术及反相烷基硅胶键合相研究

综述了以硅胶为基质的高效液相色谱填料的合成方法以及反相键合相填料的最新研究进展,对其进行了评述并提出反相填料的研究方向。     

制备硅胶键合相填料的一种新方法：硅氢加成反应

介绍了近年来高效液相色谱填料的新进展。着重讨论了一种新的制备硅胶键合相填料的方法－硅氢加成反应。较详细地叙述了该方法的原理,反应条件,机理及应用。     

苯基键合硅胶萃取黄酮化合物的性能研究

以苯基三氯硅烷和硅胶为原料制得苯基键合硅胶固相萃取材料,采用扫描电镜、元素分析、比表面积/孔径分析、红外光谱等对其进行了结构表征。装填固相萃取小柱,以4个黄酮模型化合物为目标分析物,研究苯基键合硅胶的萃取性能。对上样体积、上样速度、上样pH、洗脱剂类型、洗脱体积、洗脱速度等萃取参数进行了优化,并建立了苯基键合硅胶富集萃取黄酮化合物的高效液相色谱分析检测方法。实验证实该方法具有宽的线性范围(1~200μg/L)、低的检出限(0.25μg/L),并成功应用于2种实际样品中黄酮化合物的富集检测。上述结果说明苯基键合硅胶是一种对黄酮化合物具有良好萃取性能的固相萃取材料。     

C18反相硅胶键合相的制备与性能评价

以20~40μm无定形硅胶为载体,与十八烷基三氯硅烷进行键合制备了C18反相硅胶键合相。热重差热分析表明所得键合相230℃以下热稳定性良好,对残留硅羟基的定量测定表明采用三甲基氯硅烷进行封端反应可消除3/4以上的残留硅羟基,柱层析试验表明该键合相具有良好的分离效果。     

高效液相色谱用硅胶键合固定相的研究进展

从新型固定相，传统固定相性能的改进两个方面综述了高效液相色谱中用硅胶键合固定相近几年来的研究发展概况，并对其发展予以展望。     

丙氧基—18—冠—6硅胶键合固定相的合成及色谱性能的研究

以多孔硅胶为基质,固相合成并制备了一种新型丙氧基-18-冠-6键合固定相(P18-C-6 SB),详细研究了其合成反应条件。P18-C-6 SB 是一种热稳定性好、耐溶剂,表面键合浓度高的色谱固定相。已应用于芳香族异构体及同系物的分离。     

酸-碱催化法制备HPLC级二氧化硅微球及其十八烷基化和氨基化

采用酸-碱催化的溶胶-凝胶法制备二氧化硅微球,系统探索了水量、乙醇量、旋蒸温度、搅拌速度和致孔剂的种类对二氧化硅微球形态和粒径分布的影响,并采用显微镜、比表面积分析仪、滴定法和红外光谱法对二氧化硅微球结构进行了表征。将制得的二氧化硅微球经简单沉降筛分及功能化后,获得了四种填料C18键合硅胶、亲水C18键合硅胶、氨丙基键合硅胶、乙二胺-N-丙基键合硅胶。结果表明：最佳的二氧化硅微球制备条件为,n(H2O):n(TEOS)=6/4,V(EtOH):V(TEOS)=3/5,旋蒸温度为57 ℃,搅拌速度为2190 r/min,致孔剂为DMF。所制二氧化硅微球球形度好、粒径分布为3～10 μm、比表面积为464.11 m2/g、孔体积为1.14 m3/g、平均孔径为9.81 nm且孔径分布窄、硅羟基含量高达0.5450 mmol/g。C18键合硅胶和亲水C18键合硅胶的柱效分别为53474/m和86984/m（以甲苯计）,且对分析物的分离良好。氨丙基键合硅胶和乙二胺-N-丙基键合硅胶的离子交换容量分别为1.44和1.22 mmol/g,对甲苯磺酸吸附量分别为240.8和217.6 mg/g。     

用于蛋白质分离的大孔硅胶烷基键合固定相的制备

采用大孔硅胶和一氯硅烷制备了几种用于蛋白质水分离的大孔硅胶短链烷基键合固定相。     

大孔硅胶烷基键合固定相的制备

采用大孔硅胶和一氯硅烷制备了几种用于蛋白质分离的大孔硅胶短链烷基键合固定相。     

高效液相色谱中富勒烯的分离因子与键合相特征结构间的定量相关模型

根据分子拓扑理论 ,提出能表征液相色谱中键合相特征结构的分子拓扑指数 ,建立高效液相色谱中富勒烯分离因子与键合相特征结构间的定量相关模型 ,模型计算值与实验值符合良好。     

O—[2—（取代）邻苯二甲酰亚胺基]乙基硫代磷酸脂的合成

阐明了一系列２４个Ｏ－「２－（取代）邻苯二甲酰亚胺基」乙基硫代磷酸脂和９个转位异构化合物的合成和生物活性测定结果，并用ＨＮＭＲ，ＭＳ和元素分析方法对这些新化合物进行了结构表征。讨论了这些新化合物的波谱性质，生活性和转位异构化现象。     

Temperature selective condensation of tyre pyrolysis oils to maximise the recovery of single ring aromatic compounds

Scrap tyres were pyrolysed in a fixed bed reactor and the evolved pyrolysis gases were passed through a condenser system maintained at separately controlled temperature to determine the yield and composition of the condensed oil. The main objective was to maximise the selective condensation of single ring aromatic compounds which are of known higher commercial value. In addition, the molecular weight range of the condensed oils was also determined. The influence of condenser packing material was also examined. The results showed that the type of packing material within each condenser was also examined and found to be important in determining the yield and composition of the condensed oil. Similarly, condenser temperatures determined the yield and also composition of the oils. Maximum concentrations of single ring aromatic compounds in relation to the selective condensation process showed significant increases in the concentration of certain compounds could be achieved in the condensed oils collected in each condenser.     

Synthesis of long-chain alkanesulfonates by photosulfochlorination using sulfuryl chloride

To develop a new method for the manufacture of anionic surfactants such as alkanesulfonates, which are completely biodegradable, we used linear aliphatic hydrocarbons C₁₂ and C₁₄ as raw material. These hydrocarbons were transformed into the corresponding sulfochlorides in quantitative vield by photosulfochlorination with sulfuryl chloride. The operating conditions led to reaction mixtures containing all the position isomers of sulfochlorinated and chlorinated alkanes. These compounds have been identified by gas chromatography-mass spectrometry. The isomeric distribution of different reaction products, as well as the molar ratio of the main product, the alkanesulfochlorides, vs. the by-products, the alkanechlorides, were determined by the gas chromatogrpahy method. The particular isomeric distribution observed during these reactions was different from that of classic chain reactions, as highlighted by the values of calculated relative reactivities. After separation, purification, and alkaline hydrolysis steps, the resulting dodecane and tetradecanesulfonates showed good surface activity. Indeed, the values of the surface tensions at the critical micelle concentration (CMC) compare well with those in the literature. CMC values of these mixtures are given, and the influence of isomeric distribution on CMC values and on the surface tension values at the CMC is presented.     

Characterization of the nonvolatile compounds formed during the thermal oxidation of 1-linoleyl-2,3-distearin: II. The acidic fraction

Four compounds were isolated from the acidic fraction of 1-linoleyl-2,3-distearin which was heated at 200 C for 24 hr with aeration. Following saponification of the oxidation mixture, the fatty acids were partitioned between ethanol and pentane-hexane (Skellysolve F). The ethanol soluble acids were subsequently esterified with methanol and subjected to further separation by preparative thin layer and gas liquid chromatography. A combination of chemical and instrumental analyses as well as a comparison with standard compounds was used to determine the structures. Substances characterized were isomeric C₁₈ aromatic esters, isomeric methyl keto-octadecanoates, isomeric methyl keto-octadecenoates and dimethyl undecane-1,11-dioate. This work represents a portion of a thesis presented by L. R. Wantland as partial fulfillment of the requirements for the Ph.D. degree at the University of Illinois.     

填料粒径对制备色谱生产的影响

随着绿色精细化工工业的发展,对制备色谱和模拟移动床色谱(SMBC)的需求越来越大。填料粒径的选择是制备色谱和模拟移动床色谱分离中的关键问题。填料粒径主要从柱效和压力两方面影响着制备色谱的应用。压力影响着运行成本,柱效影响着分离效果,但两者又互相制约。该文利用板高曲线和压力变化曲线斜率积对填料性能进行了比较。斜率积消除了填料粒径的影响,却又联系着其他与柱压力和柱效相关的因素。利用斜率积来评价填料性能对问题的分析更加深入。该文通过对不同粒径填料所填充柱的孔隙率、柱压和柱效的比较发现,随填料粒径减小,柱压力的上升幅度小于随填料粒径平方反比例增大的幅度,理论塔板高度减小。从银杏黄酮的模拟移动床色谱分离结果可以看出,使用粒径为20~25μm的填料,其产品纯度低于使用粒径为30~40μm的填料。     

Chemical Strengthening of Polycrystalline Alumina

Low-expansion solid solution surface layers formed by reaction of Cr₂O₃ and Al₂O₃ were used to chemically strengthen alumina bodies. The surface layers were formed by packing the samples in Cr₂O₃ powder and heating to high temperatures. Fluorides or chlorides were added to the packing material, leading to substantial additional improvement. The flexural strengths of the control samples were increased by refiring in the presence of the products of decomposition of the fluorides. At high concentrations of fluorides in the packing material, the outside dimensions and the weights of the samples decreased during the treatments.     

热脱附-气/质联用法快速测定烟用印刷油墨中的挥发性成分

应用热脱附-气/质联用法(TDS-GC/MS)对卷烟包装材料印刷中使用的油墨挥发性成分进行了分析测定,对影响热脱附的条件进行了优化。结果表明,热脱附温度80℃,脱附时间2 min,冷阱温度-150℃为最佳组合水平。同时对方法的重现性进行了考察,各目标物的相对标准偏差小于15%(n=6)。     

New non-ionic surfactants: Alkyl polyoxyethylene diethers of isomeric dimethylxanthines

Novel isomeric nonionic surfactants of the poly-oxyethylene (POE) ether type possessing terminal dimethylxanthine functions related to caffeine have been prepared using a polyoxyethylene cetyl mono-ether as the starting material. The surface tension pro-perties indicate that, compared to the parent com-pound and its chloride derivative, these derivatives show pronounced changes in the critical micelle con-centration (CMC) and pre-CMC slope but relatively minor changes in the minimum surface tension value. The findings are discussed also in terms of efficiency and effectiveness of surfactants. The evidence indi-cates that the structure of the terminal hydrophilic portion can have a significant effect on interfacial packing. The cloud points of the chloride derivative and the xanthine derivatives were considerably lower than that of the parent ether. Cloud point curves for the ether, the chloride, and the xanthines over the dilute concentration range show similar features.     

Praktische Hinweise zur mikrobiologischen Prüfung kosmetischer Hautpflegemittel

Cosmetic Preparations: Practical Methods of Bacteriological Evaluation The microbiological evaluation of cosmetic compounds makes it imperative to adapt the usual bacteriological methods to the special composition of these compounds. Practical methods for analysis of raw-materials, intermediate and finished products, of packing material, machinery and equipment as well as a procedure for homogeneous inoculation of emulsions are described.     

Process of choking of a slide valve channel in teeming of bearing steels

Conclusions The interrelationship of the composition and structure of the skull formation in the steel teeming channel with the material used for packing the cavity of the slide valve nozzle in teeming of bearing steel, which is prone toward choking of the channel, was established.It was shown that the use of bank sand as the packing is preferable to disthene-sillimanite concentrate since the latter, reacting with the nozzle material, forms refractory compounds with deep penetration of the metal, which promotes choking of the channel, disturbance of teeming conditions, and poorer ingot quality.The use of magnesite composition refractory parts in slide valves in teeming high alloy steels is undesirable because of their increased tendency toward skull formation.Translated from Ogneupory, No. 1, pp. 14–18, January, 1984.