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151.
A simple and fast method was developed to determine non-UV active compounds directly without derivatization. The usefulness of the method was demonstrated by detecting the major components in aminoglycoside antibiotic mixtures using capillary zone electrophoresis with potential gradient detection. Under optimized separation conditions (0.2 mM cetyltrimethylammonium bromide (CTAB), 1 mM ammonium citrate, pH 3.5), gentamicin was separated into three major peaks (C1, C1a, and C2+C2a) within 15 min. This method showed better sensitivity than other capillary electrophoresis (CE) methods for determining underivatized gentamicin. The linear range was from 10 to 500 ppm. Because of its good repeatability and simplicity, this new method could be a good alternative for the current assays given by US Pharmacopoeia and European Pharmacopoeia. 相似文献
152.
H. Brtell G. Rietz S. Sandqvist M. Berg H. Ehrsson 《Journal of separation science》1982,5(11):596-603
A two- dimensional gas chromatograph based on the Deans switching principle is described. The unit comprises two separate ovens, each containing a fused silica capillary column. The columns are joined in a specially designed manifold permitting heart cuts to be performed without significant decrease in efficiency. The switching speed and the retention time stability of the system made it possible to perform heart cuts of only a few seconds' duration. The system has been used under isothermal conditions for the determination of an amino alcohol (KABI 2128) in the low ng/ml range after trifluoroacetylation and with electron capture detection. A much shorter clean-up procedure could be used in combination with the two-dimensional gas chromatograph as compared to a method using a single glass capillary column. 相似文献
153.
Martin Gilges Heribert Husmann Maria-Helen Kleemiß Stephan R. Motsch Gerhard Schomburg 《Journal of separation science》1992,15(7):452-457
Mixtures of several basic proteins have been used to test CZE capillaries with surfaces modified by new pretreatment procedures; the performance obtained has been compared with that achieved using capillaries treated by procedures described in the literature. It has been shown that addition of non-ionic polyvinylalcohols (PVA) to CZE buffer solutions deactivates even bare, i.e. untreated, fused silica surfaces and renders them suitable for separations of basic proteins. The performance obtained from such surfaces was comparable with that of capillaries modified by the more elaborate procedures of etching, silanol derivatization, and/or adsorptive coating (again with polymers). A home-made device is described which enables derivatization and coating reactions to be performed on fused silica capillaries under an inert atmosphere, i.e. one free from oxygen and water. 相似文献
154.
本文采用XE-60交联弹性石英性细管柱及407有机体埴充柱气色谱法可分分析丙烯腈中有机杂质。通过对柱长、担体粒度、液膜厚度、柱温和载气流量的选择。确定出最佳色 谱条件。 相似文献
155.
An end-channel amperometric detector with a guide tube for working electrode was designed and integrated on a home-made glass microchip. The guide tube was directly patterned and fabricated at the end of the detection reservoir, which made the fixation and alignment of working electrode relatively easy. The fabrication was carried out in a two-step etching process. A 30 μm carbon fiber microdisk electrode and Pt cathode were also integrated onto the amperometric detector. The baseline separation of dopamine (DA), catechol (CA) and epinephrine (EP) was achieved within 80 s. Relative standard deviations of not more than 5.2% were obtained for both peak currents and migration times of DA and CA (n=5). Using standard adding method, DA in tLrine and plasma samples was detected. The recoveries were in the range of 83%—103%. 相似文献
156.
157.
毛细管区带电泳法测定复方甘草片中的甘草酸、甘草次酸、吗啡和苯甲酸钠 总被引:9,自引:0,他引:9
在紫外检测波长为 2 2 8nm、电压为 14kV、背景电解质为 5 0mmol/L硼砂溶液、内标为氢氯噻嗪的条件下 ,用毛细管区带电泳法对复方甘草片中的甘草酸、甘草次酸、吗啡和苯甲酸钠进行了定量分析。结果甘草酸、甘草次酸、吗啡和苯甲酸钠的相对峰面积 (组分与内标的峰面积之比 )与各自的质量浓度之间呈良好的线性关系 ,上述 4种组分的平均回收率分别为 98 2 % ,97 3% ,97 1%和 97 5 %。方法简便、快速、准确。 相似文献
158.
A heated injection system for a microprocessor-controlled GC has been developed for the (GC)2 analysis of the volatile phase of whole smoke of a cigarette. Effects of injection port temperature and the presence of a Cambridge filter pad are demonstrated. Chromatograms are shown for smoke samples with and without a Cambridge Filter with the sample valve oven at 25°, 165° and 205°C. The use of a flame ionization and a nitrogen-phosphorous detector is illustrated. 相似文献
159.
Allyloxy bisbenzo 16-crown-5 trimethoxysilane was first used as precursor to prepare the sol-gel-derived bisbenzo crown ether/hydroxyl-terminated silicone oil (OH-TSO) SPME coating. The coating procedure involving sol solution composition and conditioning process was presented. Compared with commercial SPME stationary phases, the new coatings showed higher extraction efficiency and therefore could provide higher sensitivity for organphosphorous pesticides (OPs). Limits of detection (LODs) were in the range of 0.003-1.0 ng/g for these OPs in food samples (honey, juice, orange and pakchoi). The optimal extraction conditions of the new coatings to OPs in these samples were investigated by adjusting extraction time, salt addition, extraction temperature, and dilution ratios of samples with distilled water by using SPME coupled with gas chromatography (GC)-flame photometric detection (FPD). The method was applied to determine the concentrations of OPs in real samples. 相似文献
160.