Impregnated silica-based layers in thin layer chromatography

Abstract

Impregnated thin-layer chromatography (TLC) layers based on silica gel are presented. Impregnating agents such as metal cations, inorganic ions, chelating agents, chiral selectors, surfactants, ion-pairing reagents, and ionic liquids are discussed. The role of impregnated TLC layers in medicinal chemistry is highlighted. The historical overview of TLC separations on physically coated layers is given and some future prospects ahead of this technique are discussed.     

有机/无机杂化复合木材的制备与性能

将硅溶胶/聚丙烯酸酯,有机/无机杂化液浸注于I-69杨木材中,制成有机/无机杂化木材。FT-IR红外光谱、扫描电子显微镜分析了复合木材的微观结构和组成,结果表明,经有机/无机杂化改性后的复合木材,既保持了木材本来的性质,又具有机/无机复合物的某些特性,其力学强度和尺寸稳定性较素材显著提高。     

Use of Thermoanalytical Methods in Prediction of Thermal Endurance of Insulating Impregnating Varnishes

The results of testing the thermal properties of insulating impregnated varnishes obtained by thermoanalytical methods and based on the IEC 216 standard are presented. It was found that the temperature index determined by means of thermoanalytical testing is quite close to that derived by a conventional standardized procedure. It was also established that thermoanalytical methods could be used in the recipe selection for the development of a new varnish. The results obtained confirmed the possibility of using thermoanalytical methods for a quick, prognostic estimation of the thermal endurance of insulating impregnating varnishes. This revised version was published online in August 2006 with corrections to the Cover Date.     

N2O-C2H2火焰原子吸收光谱法测定电化学浸渍液中的钴

运用N2O-C2H2火焰原子吸收光谱法测定电化学浸渍液中的钴含量。通过试验确定了共振线、燃烧器高度、灯电流、酸性介质、火焰等实验条件。用该方法对样品中钴含量进行分析,测定结果的相对标准偏差小于1.0%(n=6),加标回收率为97.3%~98.8%。该方法适用于电化学浸渍液中钴含量的控制分析和样品系统分析。     

原子吸收光谱法测定镉镍电池浸渍液中硅

提出用一氧化二氮-乙炔火焰原子吸收光谱法测定镉镍电池浸渍液中硅含量。方法具有良好的灵敏度，干扰少，重现性好。硅量在5-50μg/mL范围内与吸光度呈良好的线性关系。其相对标准偏差均为1.0％；标准加入回收率在97.0％-103.0％范围内，适用于镉镍电池浸渍液中硅的分析。完全达到了实验室分析质量控制的要求。     

包覆型纳米CeO2@SiO2复合磨料的制备?表征及其抛光性能

以无水乙醇为溶剂,氨水为催化剂,利用正硅酸乙酯(TEOS)水解,并在500℃下煅烧1h,制备了SiO2粉体.将SiO2粉体作为内核浸渍到以硝酸亚铈、乙酰丙酮和正丙醇为原料制备的铈溶胶中,得到包覆型CeO2@SiO2复合粉体.利用XRD、SEM、TEM和FT-IR等测试手段,对所制备样品的物相结构、形貌、粒径大小、团聚情况进行表征.将所制备的包覆型CeO2@SiO2复合粉体配制成抛光浆料用于砷化镓晶片的化学机械抛光,用原子力显微镜(AFM)观察抛光表面的微观形貌,测量表面粗糙度.结果表明,采用浸渍工艺成功制备出单分散球形,粒径在400～450nm,负载均匀的包覆型CeO2@SiO2复合粉体.复合粉体中CeO2的包覆量随着铈溶胶中铈离子浓度的升高而增大.经包覆型CeO2@SiO2复合磨料抛光后的砷化镓晶片表面的微观起伏更趋于平缓,在1μm×1μm范围内表面粗糙度Ra值为0.819nm,获得了具有亚纳米量级粗糙度的抛光表面.     

纯四方相硫化氧化锆催化剂的制备及其生物柴油合成应用研究

将过硫酸铵浸渍于直接合成的纳米氧化锆晶体表面,经300-500℃高温焙烧处理获得硫化氧化锆催化剂。采用X射线衍射（XRD）、氮气吸附-脱附、氨气程序升温脱附（NH₃-TPD）、傅里叶红外光谱（FT-IR）、扫描电镜（SEM）和能谱仪（EDS）等分析手段对催化剂的结构性能进行了表征。结果表明,所有的催化剂均展现出纯四方相结构和高的结晶度。其中,经500℃热处理获得的催化剂拥有最高的硫含量和酸性位,将其应用于大豆油与甲醇酯交换反应合成生物柴油,获得了脂肪酸甲酯收率高达84.6%的催化效果,进一步表明该催化剂表面存在优越的超强酸位。