Novel preparation of organic polymer-based monolithic column by microwave irradation

Microwave irradiation was firstly attempted for the preparation of organic-based monoliths of poly（styrene-divinylbenzene- methacrylic acid）, which single step in situ polymerization was carried out during 15 min. The colunm permeability, electrophoretic and chromatographac behaviors were comparatively evaluated using pressure-assisted CEC, GEC and low pressure-driven separation modes. The largest theoretical plates for the preparing column could be close to 18,0000 plates/m for thiourea in the mode of p-CEC. It provided a viable alternative to traditional initiation means for the perparation of monolithic capillary columns.     

Characterization of Saccharomyces Sp. through determination of amino acid profiles by capillary gas chromatography

The Saccharomyces strains uvarum, montuliensis, bayanus, capensis and florentinus were grown in liquid media prepared from a 1% aqueous glucose solution to which 0.05% of ammonium sulfate or urea were added as the only nitrogen supply. The amino acids exuded during incubation were isolated by cation exchange and derivatized as the corresponding N,O-heptafluorobutyryl isopropyl esters. Separation was achieved on a highly deactivated glass capillary column coated with OV-101. A characteristic amino acid profile was obtained for each of the species studied, allowing the construction of a chemotaxonomic tree, on the basis of present or absent acids.     

用微芯片化学反应器实现酶催化化学发光测定葡萄糖的研究

葡萄糖是临床化学诊断以及食品分析中重要的检测项目 ,最常用的测定方法是采用葡萄糖氧化酶(GOD)催化葡萄糖与氧分子间反应 ,生成葡萄糖酸和过氧化氢 [1] ,而对过氧化氢的检测则可采用过氧化酶 (POD)催化鲁米诺的化学发光反应进行 [2 ] .FIA对整个过程的实现是十分有效的方式 ,但由于多采用固定化酶反应器 [3～ 5] 使其在制备及分析上较复杂且费用高 .由 Manz等[6] 提出的微型全分析系统(μ- TAS)在针对不同体系的微量分析及在线监测上均具有突出的优越性 .本文使用的含微混合器的微芯片化学反应器采用μ- TAS设计思想 ,建立了化学发…     

Preparation of a sulfonated fused-silica capillary and its application in capillary electrophoresis and electrochromatography

In the present paper, two new methods, sol-gel and chemical bonding methods, were proposed for preparation of sulfonated fused-silica capillaries. In the sol-gel method, a fused-silica capillary was coated with the sol solution obtained by hydrolysis of 3-mercaptopropyltrimethoxysilane (MPTS) and tetramethoxysilane, and followed by age; while in the chemical bonding method, a capillary was chemically bonded directly with MPTS. Then, both the resulting capillaries were oxidized with an aqueous solution of hydrogen peroxide solution (H2O2) (30%, m/m) to obtain the sulfonated capillaries. The electroosmotic flow (EOF) for the sulfonated capillaries was found to remain almost constant within the studied pH range, and greater than that of the uncoated capillary. However, the coating efficiency of the capillary prepared by chemical bonding method was higher than that by sol-gel method, by comparing their magnitude of the EOF, the degree of disguise of the silanol and reproducibility of preparation procedure. The effects of the electrolyte's concentration and the content of methanol (MeOH) on the EOF were also studied. Especially, the study of the apparent pH (pH*) on the EOF in a water-MeOH system was reported. Finally, capillary electrophoretic separation of seven organic acids was achieved within 6.5 min under optimal condition using the chemically bonded sulfonated capillary. Moreover, separation of four alkaloids on the sulfonated capillary was compared with that on uncoated capillary in different conditions. Ion-exchange mechanism was found to play a key role for separation of these four basic analytes on the sulfonated capillary.     

软刻蚀及其应用

软刻蚀是一类基于自组装和复制模塑等原理的非光刻微米和纳米加工方法。它为形成和制作微米、纳米图案提供了简便、有效、价廉的途径。在软刻蚀中，用一个表面带图案的弹性模板来实现图案的转移，其加工的分辨率可达30nm－100μm。软刻蚀是微接触印刷、复制模塑、转移微模塑、毛细微模塑、溶剂辅助微模塑等的总称。本文将简介软刻蚀的原理、方法以及它们在微米和纳米加工、微电子学、材料科学、光学、微电子机械系统、表面化学等方面的应用。     

一种新的库仑微水滴定仪的设计方法

在传统微库仑滴定仪原理的基础上，利用８７５１单片机和微机，采用对电解电流时间调制的方法以及测量精度为准则判断滴定终点，从而大大地提高了仪器的测量精度和重复性。     

Comparison between adsorption isotherm determination techniques and overloaded band profiles on four batches of monolithic columns

The adsorption isotherms of 4-tert.-butyl phenol were measured on four different monolithic columns, using three different techniques, classical frontal analysis (FA), the perturbation on a plateau method (PP) and the recently introduced numerical procedure known as the inverse numerical method (IN). This last approach requires only the recording of a few overloaded profiles and has the potential advantage of affording a dramatic decrease of the amounts of compounds, solvent, and time needed to determine accurate estimates of the coefficients of the isotherm. The reproducibility of the adsorption data measured on the four columns is discussed with reference to the specific techniques used for obtaining these data and to the most suitable equation used for modeling them. The data obtained for the different columns were highly consistent. The inverse numerical approach was confirmed to provide a powerful, accurate, and economic method for measuring single component adsorption data.     

The analysis of lubricating oil additives by supercritical fluid chromatography with packed and open tubular capillary columns

Lubricating oil additives have been analyzed by supercritical fluid chromatography on open tubular and packed capillary columns. Carbon dioxide and modified carbon dioxide were used as mobile phases and detection was accomplished by flame ionization and micro UV. Rapid and efficient analysis of the lubricating oil additives was demonstrated.     

Molecularly-imprinted polypyrrole-modified stainless steel frits for selective solid phase preconcentration of ochratoxin A

A molecularly-imprinted polymer (MIP) was prepared by electropolymerization of pyrrole (Py) onto a stainless steel frit, using ochratoxin A (OTA) as the template, in order to make a micro solid phase preconcentration (SPP) device. The OTA template was removed with 1% triethylamine (TEA) in methanol. Compared to non-imprinted polypyrrole (PPy), the molecularly-imprinted polypyrrole (MIPPy) enhanced the selective binding of OTA. The percentage recovery improved from 0 to 40% when the OTA sample solution was acidified with 1 M HCl (1% by volume). At a flow rate of 0.2 mL/min, maximum OTA binding was reached in 6 min after a total loading of 3.2 ng OTA. Final elution of the OTA was analyzed by high performance liquid chromatography (HPLC) with fluorescence detection, using 20:80 v/v acetonitrile–ammonia buffer (NH₄Cl/NH₃, 20 mM, pH 9.2) as the mobile phase. The MIPPy-SPP-HPLC results clearly demonstrated that the MIPPy-SPP device afforded selective preconcentration of OTA from red wine samples, at OTA concentration levels as low as 0.05 ppb, prior to HPLC analysis.     

微型柱在线分离-ICP-MS法测定高纯氧化铕中的14个稀土杂质

研究了微型柱在线分离-电感耦合等离子质谱法（ICP-MS）测定高纯Eu2O3中痕量Tm的方法，研制了Cyanex272负载树脂微型分离柱，优化了分离Eu2O3基体的实验条件，在线分离测定时间为25min。建立了在线柱分离测定Tm，内标补偿法直接测定其余稀土杂质的高纯Eu2O3中14个稀土杂质的ICP-MS分析方法。方法检出限为0.01μg/g-0.15μg/g，加标回收率为91.5%-110%,相对标准偏差为1.7%-4.9%。可满足快速测定99.999%Eu2O3中14个稀土杂质的要求。