共查询到20条相似文献,搜索用时 484 毫秒
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自20世纪初期,德国化学家EmilFischer首先合成了甘氨酸二肽片段,并第一次提出“peptide”(多肽)这一名词,多肽化学的研究已经历了100多年的发展.1953年,Vigneand小组首次完成了生物活性肽催产素的合成,并因此于1955年获得了诺贝尔化学奖.1963年,Merrifield提出了多肽固相合成法,并发明了第一台多肽自动合成仪,大大简化了多肽合成的流程、提高了合成的效率,从而促使多肽化学实现了飞跃式发展,Merrifield也因此获得了1984年诺贝尔化学奖.1965年,我国科学家完成了牛结晶胰岛素的合成, 相似文献
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基础化学实验室的建设与管理 总被引:2,自引:0,他引:2
化学实验室是全面完成化学教学任务的重要基地。 我院2002年建立了设备比较先进的化学实验室,给学生创造了良好的实验条件,并进行了科学化的管理,规定了各种规章制度和有关职责,较好地完成了化学教学任务。在实践中。采取:固定优秀代课教师兼管,勤工助学学生帮忙的管理办法,既减轻教师的劳动强度,又培养了学生的技能,且协调了各种关系,有利于化学教学质量的提高。 相似文献
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本文合成了含酰胺基团和不含酰胺基团的两类Gemini阳离子表面活性剂,测定了其表面活性参数,研究了酰胺基团对表面活性剂的表面活性和聚集行为的影响。结果表明,酰胺基团提高了Gemini阳离子表面活性剂的临界胶团浓度,降低了胶团聚集数,增强了胶团微极性,增大了表面活性剂的饱和吸附量。 相似文献
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一种新型超临界流体萃取-高效液相色谱在线联用系统的构建 总被引:3,自引:0,他引:3
天然产物研究一直是植物学、化学和药学的重要研究领域.通过从天然产物中寻找生物活性成分和先导物是创制新药的有效途径之一.有效成分的提取是天然产物研究中最基本和最关键的环节.超临界流体萃取(Supercritical fluid extraction,简称SFE)是近年来发展较快的一种新型样品提取技术.超临界CO2作为最常用的萃取剂已被用于天然药物中非极性和弱极性有效成分的提取,尤其是挥发性和热敏性的物质.此外,通过加入适当的添加剂还可有效地萃取极性化合物,和传统的化学方法相比, 相似文献
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An on-line supercritical fluid extraction (SFE) system coupled to a continuous flow manifold including a UV detector was used as a screening system to extract astaxanthin from crayfish, which was found to be the major carotenoid present in the samples. This compound constitutes the principal additive used to dye salmon flesh. The flow manifold was used to confirm the presence of astaxanthin in the crustacean samples. Also, an HPLC/UV-vis method was used to ascertain that this compound was the major carotenoid extracted under the optimum SFE conditions employed. The influence of SFE operating variables such as pressure, temperature, equilibration time, extraction time, trap temperature, and volume of CO2 modifier was examined in order to maximize the efficiency of analyte extraction. The use of supercritical CO2 enables the expeditious, selective, quantitative extraction of astaxanthin from crustaceans. 相似文献
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G. Hotter I. Ramis G. Bioque C. Sarmiento J. M. Fernández J. Roselló-Catafau E. Gelpí 《Chromatographia》1993,36(1):33-38
Summary The aim of this study has been the evaluation of an automated system for on-line sample preparation using solid phase extraction and HPLC purification for the measurement of prostanoids in urine. We have established the optimum precolumn and column conditions for this analysis. The manual extraction —HPLC procedure furnishes lower recoveries and higher coefficients of variation than those obtained by the automated on-line procedure. The automated system has been applied to prostanoid analysis of human urine samples from subjects exposed to lead. 相似文献
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Zhang J Zhang L Duan J Liang Z Zhang W Huo Y Zhang Y 《Journal of separation science》2006,29(16):2514-2522
A novel on-line system combining supercritical fluid extraction (SFE) and two-dimensional high performance liquid chromatography (2D-HPLC) was developed. A trap column and two three-port valves were employed to couple SFE and 2D-HPLC system, which was composed of a CN column and a monolithic silica column, connected by a 10-port dual-position valve. The analytes extracted by supercritical CO2 were completely transferred to the 2D-HPLC system. After separation in two orthogonal modes, the eluents were delivered to APCI-tandem-MS for identification of the samples. In this way, sample preparation, separation, detection, and identification were integrated into an on-line system permitting analysis of the fruiting bodies of Ganoderma lucidum, and at least 73 components in the extract were resolved with calculated peak capacity of up to 1643. 相似文献
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Gode D Martin MM Steiner F Huber CG Volmer DA 《Analytical and bioanalytical chemistry》2012,404(2):433-445
Determination of trace constituents in biological and environmental samples usually requires a pre-concentration step. While solid-phase extraction (SPE) has been widely used, it is slow, labor intensive and adversely affected by analytical errors from handling. On-line SPE eliminates some of the flaws but often suffers from solvent compatibility problems with the subsequent chromatography separation. In this study, we are presenting a technical solution for overcoming some of these compatibility issues, by utilizing a fully automated, focused SPE sample transfer technique utilizing narrow-band solvent plugs, for seamless hyphenation with high-performance liquid chromatography (HPLC) or flow injection mass spectrometry (MS). A wide range of pharmaceutical compounds was studied in different sample matrices. Short plugs of high elution strength solvent were generated by means of an electrically actuated sample loop and enrichment and transfer steps monitored using on-line SPE-MS. The impact of the solvent plugs on chromatographic separation was studied using hyphenated SPE-LC-MS. By carefully examining elution profiles of solvent plugs of different compositions, optimum conditions for quantitative elution within well-defined volumes were found for all substances. In addition, the highly focused elution bands resulted in excellent retention time and peak area reproducibilities when injected on-line onto HPLC columns. Finally, to demonstrate proof-of-principle, the fully integrated on-line SPE-LC-MS system was applied to the analysis of spiked urine and river water samples. 相似文献
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A fully automated assay for the analysis of ranitidine in serum and plasma, with and without an internal standard, was validated. It utilizes robotic solid phase extraction with on-line high performance liquid chromatographic (HPLC) analysis. The ruggedness of the assay was demonstrated over a three-year period. A Zymark Py Technology II robotic system was used for serial processing from initial aspiration of samples from original collection containers, to final direct injection onto the on-line HPLC system. Automated serial processing with on-line analysis provided uniform sample history and increased productivity by freeing the chemist to analyse data and perform other tasks. The solid phase extraction efficiency was 94% throughout the assay range of 10-250 ng/mL. The coefficients of variation for within- and between-day quality control samples ranged from 1 to 6% and 1 to 5%, respectively. Mean accuracy for between-day standards and quality control results ranged from 97 to 102% of the respective theoretical concentrations. 相似文献
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Routine determination of benzo[a]pyrene at part-per-billion in complex industrial matrices by multidimensional liquid chromatography 总被引:1,自引:0,他引:1
Champmartin C Simon P Delsaut P Dorotte M Bianchi B 《Journal of chromatography. A》2007,1142(2):164-171
A rapid and selective high performance liquid chromatography (HPLC) method using a column-switching technique has been developed for the determination of benzo[a]pyrene in complex mixtures containing polycyclic aromatic hydrocarbons. The diluted sample is directly injected into the chromatographic system without pre-treatment. The purification is performed on-line using three cleaning columns filled with various stationary phases. The sample preparation, a simple dilution, and the analysis time do not exceed 45 min. The method developed was used to analyze industrial products such as oil, bitumen, etc. and was compared with an off-line method requiring treatment and extraction steps before the analysis. 相似文献
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An automated system was developed for analysis of non-polar and polar ionisable compounds at trace levels in natural water. Sample work-up was performed in a flow system using two parallel membrane extraction units. This system was connected on-line to a reversed-phase HPLC system for final determination. One of the membrane units was used for supported liquid membrane (SLM) extraction, which is suitable for ionisable or permanently charged compounds. The other unit was used for microporous membrane liquid-liquid extraction (MMLLE) suitable for uncharged compounds. The fungicide thiophanate methyl and its polar metabolites carbendazim and 2-aminobenzimidazole were used as model compounds. The whole system was controlled by means of four syringe pumps. While extracting one part of the sample using the SLM technique. the extract from the MMLLE extraction was analysed and vice versa. This gave a total analysis time of 63 min for each sample resulting in a sample throughput of 22 samples per 24 h. 相似文献
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A high-pressure photochemical reaction cell operated with a magnetic stir drive has been directly interfaced on-line with either SFC or HPLC. The interface consisted of an oven housing a recirculation pump directly connected to a sample injection valve. The inlet of the recirculation pump and the outlet from the sample injection valve were connected to the stirred reaction cell such that a return flow circuit was established. With this arrangement, a continuous flow of fresh supercritical fluid photochemical reaction mixture was maintained through the sample injection valve. This enabled samples of reaction mixture to be conveniently analyzed at regular intervals to monitor reaction progress using either on-line SFC or HPLC. The photoreduction of benzophenone in the presence of propan-2-ol to produce 1,1,2,2-tetraphenylethane-1,2-diol and 2-methyl-1,1-diphenylpropan-1,2-diol was studied. For this reaction, on-line SFC provided significantly better performance than on-line HPLC and was therefore used to monitor overall reaction progress and the different product yields. Quantitative results for this study demonstrate that highly efficient photochemical reactions proceeded in supercritical fluid carbon dioxide at 13 and 20 MPa. 相似文献