固相微萃取技术在形态分析中的应用进展

形态分析比传统的元素分析能提供更为丰富的信息，成为当今分析化学领域前沿课题之一，而固相微萃取（SPME)是近十年来发展起来的新型分离富集技术，简便快速、无污染、易于和其它技术联用．近几年来才开始将固相微萃取应用到形态分析，二者结合对形态分析的发展具有促进作用，本文就固相微萃取技术在元素有机化合物形态分析中的应用进行了评述．     

稀土元素分离检测技术新进展

对2003年以来稀土元素分离检测技术的新进展进行了评述，重点集中于各种新型分离技术、新型检测技术及其在稀土元素分析中的应用。对于离子液体、纳米材料、离子印迹聚合物等新型材料以及浊点萃取、膜萃取、毛细管电泳等新型技术在稀士元素分离中的应用进行了详细讨论，并对中子活化分析、等离子体原子发射光谱和等离子体质谱在稀土元素检测中的应用进行了综述，重点讨论了等离子体质谱技术的应用。在回顾稀土元素分离检测技术进展的同时，对其在未来几年的发展趋势进行了评述。     

离子液基萃取金属离子的研究进展

室温离子液体作为一种新型绿色溶剂,因其具有不挥发、不易燃等重要特性,故近年来在各种金属离子液/液萃取领域的应用日益受到关注。本文系统评述了离子液基萃取金属离子的分配规律、萃取机理、缺陷和克服方法,并展望了该分离方法在环境分析化学领域的应用前景。     

《化学通报》网络版(Chemistry Online)2004年第5期论文摘要

[w0 34]微型全分析系统(︼TAS)中的微分离技术Micro- separation in Miniaturized Total Analysis System徐　溢1,2　张晓凤1　海显来1　兰宇卫1(1重庆大学化学化工学院　2重庆大学光电技术及系统教育部重点实验室重庆　4 0 0 0 4 4)介绍了微型全分析系统(μTAS)中微分离的重要性和它的概念,除了毛细管电泳芯片分离技术外,对其它诸如萃取分离、膜分离、色谱、磁分离等新兴微分离技术在μTAS中的研究和应用进行了综述,并对微流控芯片上微分离技术的进展作了评述和展望。The importance and conception of micro- separation for miniat…     

欢迎订阅《分析化学》(2004年) 邮发代号12-6

本刊承办广告业务《分析化学》(ISSN 0 2 5 3- 382 0 ,CODENFHHHDT ,CN 2 2 - 112 5 /O6 )是中国科学院和中国化学会共同主办的专业性学术期刊 ,主要报道我国分析化学创新性研究成果 ,反映国内外分析化学学科前沿和进展。刊物设有研究报告、研究简报、评述与进展、仪器装置与实验技术、来稿摘登等栏目。读者对象为从事分析化学研究和测试的科技人员及大专院校师生。本刊也是有关图书、情报等部门必不可少的信息来源。《分析化学》目前是我国自然科学核心期刊及全国优秀科技期刊 ,1999年荣获首届国家期刊奖 ,2 0 0 0年获中国科学院优…     

欢迎订阅《分析化学》(2004年)邮发代号12-6

本刊承办广告业务　　《分析化学》(ISSN 0 2 5 3- 382 0 ,CODENFHHHDT ,CN 2 2 - 112 5 /O6 )是中国科学院和中国化学会共同主办的专业性学术期刊 ,主要报道我国分析化学创新性研究成果 ,反映国内外分析化学学科前沿和进展。刊物设有研究报告、研究简报、评述与进展、仪器装置与实验技术、来稿摘登等栏目。读者对象为从事分析化学研究和测试的科技人员及大专院校师生。本刊也是有关图书、情报等部门必不可少的信息来源。《分析化学》目前是我国自然科学核心期刊及全国优秀科技期刊 ,1999年荣获首届国家期刊奖 ,2 0 0 0年获中国科学…     

欢迎订阅《分析化学》（2005年）邮发代号12—6

《分析化学》(ISSN 0 2 5 3 -3 82 0 ,CODENFHHHDT ,CN 2 2 -1 1 2 5 /O6)是中国科学院和中国化学会共同主办的专业性学术期刊 ,主要报道我国分析化学创新性研究成果 ,反映国内外分析化学学科前沿和进展。刊物设有研究报告、研究简报、评述与进展、仪器装置与实验技术、来稿摘登等栏目。读者对象为从事分析化学研究和测试的科技人员及大专院校师生。本刊也是有关图书、情报等部门必不可少的信息来源。《分析化学》目前是我国自然科学核心期刊及全国优秀科技期刊 ,1 999年荣获首届国家期刊奖 ,2 0 0 0年获中国科学院优秀期刊奖特别奖…     

样品前处理-色谱分析在线联用技术的研究进展

样品前处理是色谱分析中耗时最多、最容易引起误差的关键环节,因此有关样品前处理技术与色谱分析的在线联用的研究已成为分析化学的前沿课题。本文综述了近年来各种样品前处理技术与色谱分析在线联用的研究进展,包括固相萃取、固相微萃取与液相微萃取、膜辅助萃取、场作用辅助萃取、气相萃取、热解吸以及微芯片分离技术。     

固相萃取技术分离富集食品和环境水中铅的应用进展

综述了固相萃取的基本原理、固相萃取吸附材料和离子印迹技术,评述了固相萃取技术分离富集食品及环境水中铅的应用情况(引用文献44篇)。     

基于新型分离介质的痕量物质萃取富集与高灵敏检测技术

复杂基质中痕量组分的萃取富集与高灵敏检测一直是分析化学领域的难点和热点问题,涉及环境污染监测、食品药品安全分析、生物样品检测等领域,与人类健康息息相关.高灵敏检测通常需要对痕量目标组分进行萃取分离、净化、富集等前处理后才能实现.因此,样品前处理技术在痕量物质检测中具有重要地位.大部分样品前处理技术的核心是分离介质的选择与优化,分离介质的功能基团组成和形貌结构等理化性质直接影响着其吸附和萃取性能.本文主要综述了目前颗粒型和整体型两大类分离介质的研究进展及基于新型分离介质的萃取富集与高灵敏检测技术,并归纳了其在环境分析、食品分析、生物分析和医药分析领域中的应用.     

Chemical analysis and antiviral activity evaluation of Baccharis anomala

The chemical composition and antiviral activity of aqueous extract from Baccharis anomala was studied by bioactivity-guided fractionation. Ethanol precipitation and fractionation by molecular permeation allowed the separation of the anti-herpes simplex virus 1 (HSV-1) active fraction from aqueous extract (Fraction B). Natural Product Reagent A, FeCl₃ and thin-layer chromatography indicated the presence of phenolic compounds in the aqueous extract. Fraction B showed pronounced antiviral activity when tested with HSV-1 strains VR733/ATCC and Acyclovir-resistant 29-R, displaying virucidal but not virustatic activity.     

Preparative-scale fractionation by isoelectric trapping under nondenaturing conditions: separation of egg white protein isoforms on a modified Gradiflow unit

pH-biased isoelectric trapping was used to separate proteins from egg white at the preparative level (80 mg), into discrete protein fractions based on isoelectric point. The problems of isoelectric precipitation that are common for the separation of complex protein mixtures under isoelectric conditions were mitigated by using single-component isoelectric buffers within the sample separation compartments. This combined with the mild process conditions of the Gradiflow unit that was modified for binary isoelectric trapping separations, ensured that biological activity was maintained. This was verified by measurement of the trypsin protease inhibitory activity of the extract and separated fractions. Furthermore, the high resolving power of this system under preparative conditions was demonstrated by separation of three protein isoforms using isoelectric membranes with differences of 0.025 pH units from each other.     

Purification of serine hydroxymethyltransferase from Bacillus stearothermophilus with ion-exchange high-performance liquid chromatography.

The gene of serine hydroxymethyltransferase (SHMT) of a thermophilic bacterium Bacillus stearothermophilus was expressed in Escherichia coli, and SHMT was successfully purified from the crude extract of E. coli in two steps while maintaining the enzymatic activity. The purification steps involved ammonium sulphate precipitation followed by high-performance liquid chromatographic separation using the anion-exchange column Fractogel EMD DEAE-650(S). In addition to the DEAE column, three other types of anion- and cation-exchange columns were also studied for their ability to separate SHMT, and the performance of the four columns were compared.     

Surface molecularly imprinted polymers prepared by two‐step precipitation polymerization for the selective extraction of oleanolic acid from grape pomace extract

Surface molecularly imprinted polymers were successfully prepared by a novel two‐step precipitation polymerization method. The first‐step allowed the formation of 4‐vinylpyridine divinylbenzene and trimethylolpropane trimethacrylate copolymeric microspheres. In the second‐step precipitation polymerization, microspheres were modified with a molecularly imprinting layer of oleanolic acid as template, methacrylic acid as functional monomer, and divinylbenzene/ethylene glycol dimethacrylate as cross‐linker. The obtained polymers had an average diameter of 4.43 μm and a polydispersity index of 1.011; adsorption equilibrium was achieved within 40 min, with adsorption capacity reaching 27.4 mg/g. Subsequently, the polymers were successfully applied as the adsorbents of molecularly imprinted solid‐phase extraction to separate and purify the oleanolic acid from grape pomace. The content of oleanolic acid in the grape pomace extract was enhanced from 13.4 to 93.2% after using the molecularly imprinted solid‐phase extraction process. This work provides an efficient way for effective oleanolic acid separation and enrichment from complex matrices, which is especially valuable in industrial production.     

A novel general and efficient technique for dissociating antigen in circulating immune complexes

Circulating immune complexes (CICs) are produced during the immune response. It is more clinically important to establish a general and efficient CICs dissociation technique for the detection of antigens for CICs other than the detection of free antigens in the serum. Polyethylene glycol (PEG) two‐precipitation separation and glycine‐HCl as a buffer system were employed to develop a general and efficient buffer dissociation technique to separate CICs from serum and dissociate antigens from CICs. The measurement value of new PEG two‐precipitation separation technique was higher than traditional PEG precipitation separation technique. There were slight differences in the dissociation conditions of HCV Core‐IC, HIV P24‐IC, Ins‐IC and TG‐IC as compared to HBsAg‐IC. The detection of antigens in HBsAg‐IC, HCV Core‐IC, HIV P24‐IC, Ins‐IC and TG‐IC with this technique was superior to that with HCl Dissociation, Trypsin Digestion or Immune Complex Transfer technique. PEG two‐precipitation dissociation technique may reduce macromolecular protein and the adhesion of free antigens during the co‐precipitation, which increases the efficiency of separation and precipitation of CICs. This technique also avoids the damage of reagents to antigens, assuring the repeatability, reliability and validity. Thus, this technique is application in samples negative or positive for free antigens.     

Determination of antimony in rocks and sulphide ores by flame and electrothermal atomic-absorption spectrometry

Atomic-absorption methods for determination of antimony at mug/g levels in rocks and sulphide ores by flame atomization (FAA) and electrothermal atomization (ETAA) have been described. The FAA method involves the separation of antimony from matrix elements by extraction as the iodide into methyl isobutyl ketone containing tri-n-octylphosphine oxide, from dilute hydrochloric acid solution, followed by direct aspiration of the extract into an air-acetylene flame. If necessary, antimony is first separated from copper and lead by co-precipitation with hydrous ferric oxide from ammoniacal medium and by precipitation of lead as lead sulphate. The ETAA method involves co-precipitation of antimony with hydrous ferric oxide followed by dissolution of the precipitate in dilute nitric acid, mixing with nickel solution as releasing agent, and ETAA measurement by use of a tungsten strip atomizer.     

Applicability of reversed-phase liquid chromatography for the speciation of vanadyl and nickel metalloporphyrins in oil extracts

Summary Gradient reversed-phase liquid chromatography was examined with a view to using it as a separation technique for the speciation of vanadyl and nickel porphyrins in oil extracts. Poor separations were obtained when precipitation of the sample constituents occurred in the starting mobile phase. The reasons for the precipitation phenomena were found to be highly complex. Mixed crystal formation, slow dissolution kinetics and saturation may influence the elution behaviour of species present in the oil extracts. When precipitation was avoided the separation of the vanadyl porphyrins was significantly improved. Thus far, no satisfactory separations have been obtained for the nickel porphyrinic species.Although the occurrence of precipitation of the extracts hinders the distinct speciation of metalloporphyrins with reversed phase chromatography, the precipitation/dissolution phenomena showed some interesting features as a clean-up step for diluted crude oil samples and oil fractions.     

漆酚酯键合硅胶液相色谱固定相的制备与应用

以甲基丙烯酸漆酚酯为色谱配体,制备了一种新型色谱固定相。首先以漆酚和甲基丙烯酰氯为原料制备得到甲基丙烯酸漆酚酯,并通过物理吸附涂覆到由3-（甲基丙烯酰氧）丙基三甲氧基硅烷化学修饰的硅胶上,再通过自由基引发与硅烷化硅胶的双键聚合制得漆酚酯键合硅胶固定相（USP）。对固定相进行傅里叶红外光谱（FT-IR）、热重分析（TGA）、扫描电子显微镜（SEM）和元素分析（EA）表征,结果表明通过共聚反应成功地将漆酚酯固定在硅烷化硅胶上,且制备出的固定相具有良好的单分散性。采用匀浆法装柱,以乙腈-0.05%磷酸溶液（3：97,v/v）为流动相,流速为0.4 mL/min,检测波长为220 nm,考察固定相对天麻浸膏的分离性能。以乙腈-水（50：50,v/v）为流动相,流速为0.5 mL/min,检测波长为290 nm,考察固定相对吴茱萸浸膏的分离性能。结果表明该固定相对天麻浸膏和吴茱萸浸膏均具有良好的分离性能,从天麻浸膏中分离出5个色谱峰,从吴茱萸浸膏中分离出2个色谱峰。与商品化C₁₈ 柱相比,USP柱可以从天麻浸膏中分离出更多的有效组分并实现基线分离,分离吴茱萸浸膏的色谱条件更为环保和安全。采用低流速对天麻浸膏和吴茱萸浸膏进行分离,减少了流动相的使用量,分离结果令人满意。以天然产物漆酚制备色谱固定相,既为分离纯化天麻素和吴茱萸碱提供了一种新的方法,又为液相色谱固定相制备提供了新的思路,还拓展了生漆在色谱分离材料方面的应用。     

Substoichiometric precipitation of silicon as barium fluorosilicate

Distillation and substoichimetric precipitation for silicon have been developed for the determination of trace amounts of silicon. It is based on substoichiometric precipitation as barium fluorosilicate and the distillation of silicon tetrafluoride. The separation has been applied for the determination of silicon in gallium arsenide and NBS steel as standard reference material.     

Optimization of the fractional precipitation of paclitaxel from a Taxus chinensis cell culture using response surface methodology and its isolation by consecutive high‐speed countercurrent chromatography

A consecutive preparation method for the isolation and purification of paclitaxel from the Taxus Chinensis cell culture was developed in this study. The process involved alkaline Al₂O₃ chromatography, fractional precipitation, and high‐speed countercurrent chromatography. The original cell culture materials were first extracted with methanol using ultrasound‐assisted extraction, and then the extract (the content of paclitaxel is 1.5%) was separated by alkaline Al₂O₃ column chromatography. Subsequently, fractional precipitation was used to obtain paclitaxel. In particular, response surface methodology was used to optimize the factors of fractional precipitation (methanol concentration, material‐to‐solvent ratio, and precipitating time were optimized as 48.14%, 8.85 mg/mL, and 48.71 h, respectively) and the yield of fractional precipitation product was 30.64 ± 0.60 mg (the content of paclitaxel is 89.3%, 27.37 ± 0.54 mg) from a 100 mg fraction by Al₂O₃ column separation (the content of paclitaxel is 32.4%). Then, the product was used for further isolation by high‐speed countercurrent chromatography. About 1.00 g paclitaxel (200 ± 2 mg in each loading) with a purity up to 99.61% was isolated from 1.25 g of fractional precipitation product with a solvent system of n‐hexane/ethyl acetate/methanol/water (1.2:1.8:1.5:1.5, v/v/v/v) in one run of five consecutive sample loadings without exchanging a new solvent system.