茶多酚的色谱分析法

 对茶多酚的主要成分――儿茶素的色谱分析法进行了综述。重点介绍了应用最多的反相高 效液相色谱法,同时简述了平板色谱法、气相色谱法以及目前出现的新的色谱分析方法。     

Development and validation of stability indicating chromatographic methods for simultaneous determination of citicoline and piracetam

Citicoline and piracetam were subjected separately to different stress conditions as recommended by the international conference on harmonization. In addition, new stability indicating thin layer chromatographic and ultra high performance liquid chromatographic methods have been developed and validated for simultaneous determination of citicoline and piracetam in presence of their degradation products. Separation on the proposed thin layer chromatographic method was carried out using a developing system containing methanol:chloroform:ammonium chloride buffer (9:1:2, v/v/v) on silica gel plates at 230 nm. On the other hand, the mobile phase in the ultra high performance liquid chromatographic method was composed of water (containing 0.1% triethylamine):ethanol (92:8, v/v). The flow rate was 1 mL/min and ultraviolet detection was at 230 nm. Moreover, results of the developed methods were statistically compared to those obtained by the reported high‐performance liquid chromatography method and no significant difference between them was found. The greenness profile of ultra high performance liquid chromatographic method was assessed and compared with those of the previously published high‐performance liquid chromatography methods, it was noticed that the proposed ultra high performance liquid chromatographic method more environmentally friendly and greener than other methods.     

Comparison of ultra high performance supercritical fluid chromatography,ultra high performance liquid chromatography,and gas chromatography for the separation of synthetic cathinones

A comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones has been conducted. Nine different mixtures of bath salts were analyzed in this study. The three different chromatographic techniques were examined using a general set of controlled synthetic cathinones as well as a variety of other synthetic cathinones that exist as positional isomers. Overall 35 different synthetic cathinones were analyzed. A variety of column types and chromatographic modes were examined for developing each separation. For the ultra high performance supercritical fluid chromatography separations, analyses were performed using a series of Torus and Trefoil columns with either ammonium formate or ammonium hydroxide as additives, and methanol, ethanol or isopropanol organic solvents as modifiers. Ultra high performance liquid chromatographic separations were performed in both reversed phase and hydrophilic interaction chromatographic modes using SPP C18 and SPP HILIC columns. Gas chromatography separations were performed using an Elite‐5MS capillary column. The orthogonality of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography was examined using principal component analysis. For the best overall separation of synthetic cathinones, the use of ultra high performance supercritical fluid chromatography in combination with gas chromatography is recommended.     

HPLC-ELSD法测定生物柴油中游离甘油含量

建立了高效液相色谱(HPLC)-蒸发光散射(ELSD)法测定生物柴油中游离甘油的方法。用水萃取生物柴油中的甘油,选用强酸型阳离子交换柱(Ultimate XB-SCX)分离甘油和杂质,流动相为乙腈-水(25:75,V:V),柱温35℃;ELSD漂移管温度30℃,载气压力360 kPa。结果表明:在7.12～307.31 mg/kg范围内,甘油峰面积和其浓度的对数具有良好的线性相关性,相关系数r为0.9929。甘油的回收率为96.3%～105.6%,RSD均小于2.0%(n=5)。最低检测限(LOD)和最低定量限(LOQ)分别为2.50 mg/kg、7.12 mg/kg。该研究为生物柴油中游离甘油的提取和检测提供了一种快速高效的方法。     

Recent development trends for chiral stationary phases based on chitosan derivatives,cyclofructan derivatives and chiral porous materials in high performance liquid chromatography

The separation of enantiomers by chromatographic methods, such as gas chromatography, high‐performance liquid chromatography and capillary electrochromatography, has become an increasingly significant challenge over the past few decades due to the demand of pharmaceutical, agrochemical, and food analysis. Among these chromatographic resolution methods, high‐performance liquid chromatography based on chiral stationary phases has become the most popular and effective method used for the analytical and preparative separation of optically active compounds. This review mainly focuses on the recent development trends for novel chiral stationary phases based on chitosan derivatives, cyclofructan derivatives, and chiral porous materials that include metal‐organic frameworks and covalent organic frameworks in high‐performance liquid chromatography. The enantioseparation performance and chiral recognition mechanisms of these newly developed chiral selectors toward enantiomers are discussed in detail.     

新型碳纳米管色谱固定相制备的研究进展

碳纳米管（CNTs）作为一种新型的功能材料,具有优异的物理、化学和机械性能,已经在分析化学领域得到了广泛的关注和应用。通过填充法或原位化学气相沉积法,可制备CNTs气相色谱固定相;将CNTs沉积在硅胶微球或有机聚合物基质微球表面,可制备填充式CNTs液相色谱固定相;通过包埋共聚法将CNTs嵌入聚合物整体柱内,可制备毛细管CNTs液相色谱整体柱。本文主要综述了近年来CNTs（单壁碳纳米管和多壁碳纳米管）用于色谱固定相制备的研究现状,包括气相色谱及液相色谱,并对该领域今后的发展进行展望。     

HPLC-ELSD法测定生物柴油中的游离甘油

采用液液萃取及高效液相色谱-蒸发光散射检测技术,建立了生物柴油中游离甘油含量的测定方法.待测生物柴油经乙腈-水(75:25)抽提并离心分离后,取部分下层水相进行分析.优化的色谱条件为:色谱柱Inertsil NH2 (250 nun ×4.6 mm,5μm );流动相为乙腈-水(75:25);流速1.0 mL/min;...     

Caffeine Determination in Human Saliva and Urine by TLC and Ultraviolet Absorption Densitometry

A quantitative method using thin-layer chromatography (TLC) plates with concentrating zone and ultraviolet absorption densitometry is described for caffeine (CAF) determination in human saliva and urine. The applicability of the CAF method was tested for saliva and urine from male individuals. The changes of salivary CAF, urinary CAF concentration and of urinary CAF excretion correspond with results of previous investigations using gas chromatography, high performance liquid chromatography, radioimmunoassay or enzyme immunoassay methods. In summary, the thin-layer chromatography/densitometry method here described is easy to perform, reproducible and accurate. Thus, it is suitable for routine analysis of CAF in human saliva or urine, being an effective alternative to other, more expensive and more time-consuming chromatographic or immunological methods.     

Progress in liquid chromatography of synthetic electroneutral polymers

Recent achievements and anticipated future progress in high performance liquid chromatography of synthetic electroneutral polymers (polymer HPLC) are briefly reviewed. Basic retention mechanisms of polymer HPLC are explained and corresponding separation procedures are discussed. Advantages, drawbacks and pitfalls are presented of the most important polymer HPLC method, namely size exclusion chromatography. Principles of polymer HPLC methods combining various separation mechanisms within one chromatographic column (coupled procedures) or in a set of different chromatographic columns (two- and multi-dimensional procedures) are outlined.     

Carbon‐based sorbents in chromatography. New achievements

The newest results in the employment of carbon‐based composites in various chromatographic techniques such as gas–liquid chromatography, high‐performance liquid chromatography and electrically driven separation techniques for the separation, quantitative determination and identification of a wide variety of compounds in complicated matrices are compiled. The results are concisely described and critically evaluated. The future trends in the application of carbon‐based compounds in the chromatographic separation methods are briefly discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

芯片液相色谱技术进展

微型化是现代分析仪器发展的重要趋势。微型化液相色谱仪器在提供与常规尺度液相色谱相同甚至更高分离效率的同时,可以有效减少溶剂和样品的消耗;在液相色谱-质谱联用中,低流速进样可以有效提高质谱离子源的离子化效率,提高质谱检测效率;对于极微量样品的分离,微型化的液相色谱可以有效减少样品稀释;液相色谱的微型化还有利于液相色谱仪器整体的模块化和集成化设计。芯片液相色谱是在微流控芯片上制备色谱柱并集成相应的流体控制系统和检测系统。芯片液相色谱是色谱仪器微型化的一种重要方式,受到学术界和产业界的普遍关注,但是这一方式也充满挑战。液相色谱微流控芯片需要在芯片基底材料、芯片色谱柱的结构设计、微流体控制技术、检测器技术等方面做出创新,使微流控芯片系统适配液相色谱分离技术的需要。目前芯片液相色谱领域面临的主要问题在于芯片基底材料的性质难以满足芯片液相色谱进一步微型化和集成化的需求;因此芯片液相色谱在未来的发展中需要着重关注新型微流控芯片基底材料的开发以及微流控芯片通道结构的统一设计。该文着重介绍了芯片液相色谱技术近年来的研究进展,并简要展示了商品化芯片色谱当前的发展情况。     

Quantification of trace fatty acid methyl esters in diesel fuel by using multidimensional gas chromatography with electron and chemical ionization mass spectrometry

Measurement of contamination of marine and naval diesel fuels (arising from product mixing or adulteration) with biodiesel or fatty acid methyl esters can be problematic, especially at very low levels. A suitable solution for this task for trace amounts of individual fatty acid methyl esters with resolution and quantification can be achieved by using a multidimensional gas chromatographic approach with electron and chemical ionization mass spectrometric detection. A unique column set comprising a 100 m methyl‐siloxane nonpolar first dimension column and high‐temperature ionic liquid column in the second dimension enabled identification of individual fatty acid methyl esters at below the lowest concentrations required to be reported in a diesel fuel matrix. Detection limits for individual fatty acid methyl esters compounds ranged from 0.5 to 5.0 mg/L, with excellent linearity up to 5000 mg/L and repeatability of the method from 1.3 to 3.2%. The method was applied to the analysis of diesel fuel samples with suspected biodiesel contamination. Contamination at 568 mg/L was calculated for an unknown sample and interpretation of the results permitted the determination of a likely source of the contamination.     

以亚临界水为流动相的高效液相色谱方法的进展

由于纯水在高温高压下形成亚临界液体水时氢键网络发生改变,导致其极性、粘度等物理性质产生较大的变化。以亚临界水为流动相的高效液相色谱方法(SubWC)是近年来发展起来的一种新型分离技术。SubWC的仪器系统可以采用通过改装的一般的气相色谱(GC)或液相色谱(LC)装置;分离色谱柱既可以采用液相色谱填充柱,也可以采用类似于GC的毛细管柱;选择性既可以通过调节柱系统的温度和压力,也可以通过在流动相中添加有机调节剂或盐类进行调节;检测既可用氢火焰离子化检测器检测,也可用紫外检测器检测,极大地拓宽了色谱分离和最佳条件选择的范围。SubWC无论在仪器系统、流动相的洗脱还是固定相的选择等方面均有一定的特征。这种新的分离模式目前尚处于研究与开发阶段,且多用于极性、中等极性样品的快速分离。     

Fast and comprehensive analysis of secondary metabolites in cocoa products using ultra high‐performance liquid chromatography directly after pressurized liquid extraction

Fast methods for the extraction and analysis of various secondary metabolites from cocoa products were developed and optimized regarding speed and separation efficiency. Extraction by pressurized liquid extraction is automated and the extracts are analyzed by rapid reversed‐phase ultra high‐performance liquid chromatography and normal‐phase high‐performance liquid chromatography methods. After extraction, no further sample treatment is required before chromatographic analysis. The analytes comprise monomeric and oligomeric flavanols, flavonols, methylxanthins, N‐phenylpropenoyl amino acids, and phenolic acids. Polyphenols and N‐phenylpropenoyl amino acids are separated in a single run of 33 min, procyanidins are analyzed by normal‐phase high‐performance liquid chromatography within 16 min, and methylxanthins require only 6 min total run time. A fourth method is suitable for phenolic acids, but only protocatechuic acid was found in relevant quantities. The optimized methods were validated and applied to 27 dark chocolates, one milk chocolate, two cocoa powders and two food supplements based on cocoa extract.     

树状大分子接枝型聚合物色谱分离材料研究进展

随着色谱固定相制备技术和材料科学领域的不断发展,目前已经有大量修饰方法和新型材料被用于固相萃取、高效液相色谱以及离子色谱聚合物固定相填料的功能化修饰。其中聚酰胺-胺(PAMAM)树状大分子由于其独特的结构和性质,在色谱分离材料结构完善和性能提升中也发挥了重要的作用。该文主要综述了PAMAM树状大分子在以聚合物为基质的色谱分离材料修饰中的应用,并对其今后的发展进行了展望。     

Electrochemical Determination of Organic Compounds in Automotive Fuels

This article critically reviews the electroanalytical methods devoted for the determination of organic compounds in automotive fuels that can range from contaminants to additives typically introduced into liquid biofuels and liquid fossil fuels. Contaminants such as aldehydes and ketones in bioethanol, free fatty acids and glycerol in biodiesel, and sulfur and nitrogen organic compounds in gasoline and diesel fuel, and additives such as colour markers and antioxidants added to fuels were determined by electroanalytical methods. Special focus is given to electrodes, electrochemical techniques, and sample preparation strategies. Future directions of research on electroanalysis of liquid fuels are presented.     

金属络合物高效液相色谱—光度分析进展

本文评述了金属络合物高效液相色谱分析近期进展,包括了基本方法,色谱及光度检测条件。在有机相、水相和胶束相中形成的络合物可直接注入到色谱系统,或是将金属离子溶液注入到含有络合剂的流动相中。HPLC已成为痕量金属元素分析的极好方法。     

碳酸二甲酯与苯酚酯交换合成碳酸二苯酯的HPLC分析

用HPLC分析碳酸二甲酯与苯酚酯交换合成的碳酸二苯酯，克服了GC法分析由于高温导致碳酸二苯酯分解造成含量偏低的问题，建立了针对性强、操作简单、精密度和准确度高的HPLC分析方法。     

Analysis of turkish lignite tar by coupled LC/GC,GC/MS,and capillary SFC

This work describes the analysis of a pyrolysis product of a lignite sample obtained from the Turkish Goynuk reserve. The aliphatic, aromatic and polar compounds present in the tar are separated and identified by various chromatographic techniques: Capillary gas chromatography/mass spectrometry (GC/MS), on-line high performance microbore liquid chromatography/capillary gas chromatography (LC/GC) and capillary supercritical fluid chromatography (SFC). The suitability of each technique for this particular application is discussed, and semi-quantitative results are presented for the major components detected.     

Applications of monolithic columns in gas chromatography and supercritical fluid chromatography

Porous monoliths are well‐known stationary phases in high‐performance liquid chromatography and capillary electrochromatography. Contrastingly, their use in other types of separation methods such as gas or supercritical fluid chromatography is limited and scarce. In particular, very few studies address the use of monolithic columns in supercritical fluid chromatography. These are limited to silica‐based monoliths and will be covered in this review together with an underlying reason for this trend. The application of monoliths in gas chromatography has received much more attention and is well documented in two reviews by Svec and Kurganov published in 2008 and 2013, respectively. The most recent studies, covered in this review, build on the previous findings and on further understanding of the influence of preparation conditions on porous properties and chromatographic performance of poly(styrene‐co‐divinylbenzene), polymethacrylate, and silica‐based monolithic columns while expanding to polymer‐based monoliths with incorporated metal organic frameworks and to vinylized hybrid silica monoliths. In addition, the potential application of porous layer open tubular monolithic columns in low‐pressure gas chromatography will be addressed.