制备气相色谱仪的改进及应用研究进展

气相色谱已经成为一种常规的分析手段,但以制备为目的的气相色谱的应用还较少.目前尚没有商品化的制备气相色谱仪,需要对传统的分析型气相色谱仪加以改进,以达到高效分离制备目标化合物的目的.本文综述了国内外对制备气相色谱仪改进工作的研究进展,包括汽化室、色谱柱、分流装置、收集系统等的改进.另外,总结了制备气相色谱在各领域的应用...     

全二维气相色谱用于轻质石油馏分中芳烃含量的测定

建立了采用全二维气相色谱(GC×GC)技术一次进样完成轻质石油馏分中非芳烃、一环芳烃和二环芳烃的分离、定性 和定量。通过对柱系统的选择和色谱条件的优化,实现了一次全二维气相色谱分析即完成轻质石油馏分的族组成分离以及 目标化合物的分离。方法的加标回收率为89.5%～106.1%;样品中各组分含量重复测定的相对标准偏差均不大于5.8%,能 够满足样品测定的精密度和准确性要求,且完成1次分析最多只需要30 min。     

吹扫/捕集-热脱附气质联用法对荷叶挥发油成分的对比分析

采用同时蒸馏萃取提取得到荷叶挥发油, 通过吹扫/捕集-热脱附法(P&T-TD)对上述提取物中挥发性成分进行富集, 以气质联用(GC/MS)进行定性检测, 同时与直接进样GC/MS法分析的成分进行比较. 两种方法成功分离分析出有机酸、酯、醛、醇、酚、烷烃、芳香烃、烯烃以及含氮、硫、氧杂原子的化合物等共计84种成分, 其中P&T-TD GC/MS鉴定出63种有机化合物, GC/MS鉴定出41种有机化合物, 有20种成分共同检出. 对比分析表明: P&T-TD GC/MS的吹扫/捕集-热脱附过程能富集各种组分, 相比GC/MS分析, 可以鉴定出微量成分及更多挥发性和半挥发性成分, 在精油等挥发性成分的分析检测中使用优势明显.     

亲水/反相二维色谱法制备桔梗中的三萜皂苷

建立了亲水/反相二维色谱用于制备桔梗中三萜皂苷单体的方法。桔梗经水煮醇沉、反相和亲水两种模式的固相萃取后得到三萜皂苷类组分。选定XAmide色谱柱（150 mm×20 mm,5 μm）,以乙腈和水为流动相,在亲水色谱模式下进行组分制备。选择时间触发模式,以1 min为单位进行馏分收集,得到6~25 min之间的20个三萜皂苷精细组分。以第18个馏分（JG23）为例,在反相色谱模式下采用Atlantis Prep T3色谱柱（100 mm×30 mm,5 μm）制备,得到两个单体化合物。通过质谱和核磁共振对其进行定性,确定分别为deapi-platycoside E和platycoside E。实验结果表明,该制备方法具有好的正交选择性,对于复杂样品中三萜皂苷类化合物的分离纯化有一定的借鉴意义。     

半制备型高效液相色谱结合气相色谱-质谱联用法分析卷烟烟气中性香味成分

采用半制备型高效液相色谱结合气相色谱-质谱联用法对卷烟烟气中性香味成分了进行分析。用剑桥滤片捕集卷烟主流烟气粒相物,用同时蒸馏萃取法提取并分离得到中性香味成分。通过对半制备高效液相色谱分离条件和制备馏分体积进行优化,使复杂的烟气中性成分得到预分离,制备出组成相对简单的12个馏分,然后用气相色谱-质谱联用法分析鉴定其中香味成分。结果表明:从各馏分的总离子流色谱图中共鉴定出319种中性成分,其中烃类48种,醛类29种,酮类134种,酯类21种,醇类28种,含氧杂环类18种,含氮化合物32种,酚类7种,醚类2种。方法适合于复杂的烟气中性成分的分析研究。     

具有较高样品利用率的毛细管气相色谱-质谱的连接方法

一、前言气相色谱-质谱联用(GC/MS)因兼有优良的分离能力,较高的灵敏度和丰富的结构鉴别信息而被公认为分析挥发性复杂有机混合物的最有效的方法。我们从1975至1980年间用有机溶剂萃取富集,用填充柱的GC/MS分离分析松花江水中有机污染物,历时六年累计检出化合物只有64种,1981年采用大孔网状树脂吸附富集以加大富集倍数(采水样25升),采用玻璃毛细管气相色谱柱(GCGC或GC~2)以替换填充柱,增强了     

液相色谱-毛细管气相色谱/质谱离线联用分析烟草中的挥发性及半挥发性成分

建立了一种用于烟草样品中挥发性、半挥发性成分分析的液相色谱-毛细管气相色谱/质谱(LC-CGC/MS)离线联用方法。研究了LC-CGC/MS的分离机理。LC分析选用氨基分析柱(250 mm×2.0 mm, 5 μm)作为分析柱,正己烷-二氯甲烷-乙腈(90:6.6:3.4, v/v/v)作为流动相,对挥发性、半挥发性成分进行分离,收集得到5个馏分,并存放在5个氮吹瓶中。多次进样并收集相同时间段的馏分,氮吹浓缩至1 mL,然后分别进行CGC/MS分析,所用的CGC柱为DB-5MS(60 m×0.25 mm×0.25 μm)。结果显示,与直接采用CGC/MS分析相比,采用LC-CGC/MS分析复杂样本的效果更好,定性的可靠性更高。     

全二维气相色谱法用于不同石油馏分的族组成分布研究

一直以来采用化学法、色谱法或质谱法等多种方法联用分析不同石油馏分中一 些目标化合物和芳烃含量，但这些方法操作繁琐，迫切需要改进。作者采用全二维 气相色谱方法（GC×GC）研究不同沸程范围的蒸馏汽油、煤油柴油和裂化柴油的烷 烃（P）、烯烃＋环烷烃（O＋N）和1－4环芳烃（A）的族分离新方法。经过对柱系 统进行选择和对色谱条件进行优化，一个GC×GC方法即可实现对不同石油馏分的族 组成分离和目标化合物分离。用标准物对油品中一些特征组分进行定性，并对特征 组分和不同沸程的石油馏分的P，（O＋N），A族组成进行定量和比较，定量结果的 相对标准偏差（RSD）≤2.3。一个GC×GC方法便可完成原来要几个美国测试和材料 协会（ASTM）方法才能完成的任务。     

基于双回路技术的二维色谱在线/离线接口设计与评价

双回路技术是一套机械传动组件和流路系统,具有自动进样和馏分收集的双重功能。本研究基于双回路技术设计了一种二维液相色谱在线/离线接口,用以有效连接两种不同分离模式构建分离系统,提高系统峰容量,并对其功能进行了评价。以4种芳香族化合物为分离对象,利用设计的接口连接1套液相色谱系统,实现了进样、馏分收集、再进样纯度分析的多重操作集成;连接2套液相色谱系统,采用强阳离子交换模式对5种蛋白质样品进行初步分离,收集难分离组分,并通过再次进样到反相色谱模式的分离系统中,组分得到良好分离。进一步基于此接口连接1套强阳离子交换系统和1套微柱反相色谱系统,对牛血清白蛋白酶解产物进行在线二维分离,以1 m AU为积分阈值,共识别292个色谱峰。新型在线/离线接口可灵活实现样品微量制备、难分离组分的精细拆分和复杂样品的二维分离,为二维色谱系统的构建及分离研究提供了有力工具。     

反相液相制备色谱法结合超临界流体制备色谱法分离纯化海风藤中的化合物

建立了基于反相液相制备色谱和超临界流体制备色谱的组合方法,用于分离纯化醇提水沉后石油醚层中的海风藤。首先以甲醇作为改性剂,采用醇提水沉法去除海风藤甲醇提取物中的叶绿素,加入硅藻土后用石油醚回流富集目标成分。选用反相C18制备色谱柱将其分为18个组分,然后将组分在SFC模式下进行制备。选用酰胺色谱柱,以甲醇为改性剂,在柱温30℃、背压15.0 MPa的条件下进行分离。基于反相色谱和超临界流体色谱不同的分离选择性,最后分离得到6个高纯度化合物。该法展示了反相制备色谱和超临界流体制备色谱在海风藤分离纯化方面的优势,特别是超临界流体色谱在天然产物的分析和制备方面的巨大潜力。     

Infrared methods for high throughput screening of metabolites: food and medical applications

Chemical and physiological properties are related to individual or bioactive compounds such as essential oils, terpenoids, flavonoids, volatile compounds and other chemicals which are present in natural products in low concentrations (e.g. ppm or ppb). For many years, classical separation, chromatographic and spectrometric techniques such as high performance liquid chromatography (HPLC), gas chromatography (GC), liquid chromatography (LC) and mass spectrometry (MS) have been used for the elucidation of isolated compounds from different matrices. Hence, the use of standard separation, chromatographic and spectrometric methods was found useful in chemical and both plant and animal physiology studies, for fingerprinting and comparing natural and synthetic samples, as well as to identify single active compounds. It has been generally accepted that a single analytical technique will not provide sufficient visualization of the metabolome, hence holistic techniques are needed for comprehensive analysis. In the last 40 years near infrared (NIR) spectroscopy became one of the most attractive and used methods of analyzing agricultural related products and plant materials which provide simultaneous, rapid and non-destructive quantitation of major. This technique has been reported to determine other minor compounds in plant materials such as volatile compounds and elements. The aim of this short review is to describe some recent applications of NIR spectroscopy combined with multivariate data analysis for high throughput screening of metabolites with an emphasis on food and medical applications.     

Separation of Isomers on Nematic Liquid Crystal Stationary Phases in Gas Chromatography: A Review

Understanding the composition of complex hydrocarbon mixtures is important for environmental studies in diverse fields, but many prevalent compounds cannot be confidently identified using traditional gas chromatography (GC) techniques. Increasing requirements on analyses of isomeric compounds and the problems encountered in their separation demand a study of more efficient systems which exhibit a high selectivity. Kelker and Fresenius first used nematic liquid crystals as stereospecific stationary phases in GC. Nematic liquid crystal has shown this particular selectivity and sensitivity as stationary phases for the separation of isomers having similar volatilities. Because of their unique selectivity towards rigid solute isomers, liquid crystal stationary phases were considered at one time to be a very promising class of materials that give gas chromatographic separations very different from those that can be obtained with any other stationary phase. Since then, a great deal of attention has been paid to the separation properties of this relatively wide group of substances. Liquid crystal can be used to separate a variety of compounds including isomer mixtures which cannot be separated on conventional stationary phases. This paper aims to review all specific experimental results and presents a comparative analytical study of monomeric nematic liquid crystal stationary phases used in GC. A further contribution of this review is in the field of isomeric compounds separation.     

Gas chromatography vacuum ultraviolet spectroscopy: A review

Accelerated technological progress and increased complexity of interrogated matrices imposes a demand for fast, powerful, and resolutive analysis techniques. Gas chromatography has been for a long time a ‘go‐to’ technique for the analysis of mixtures of volatile and semi‐volatile compounds. Coupling of the several dimensions of gas chromatography separation has allowed to access a realm of improved separations in the terms of increased separation power and detection sensitivity. Especially comprehensive separations offer an insight into detailed sample composition for complex samples. Combining these advanced separation techniques with an informative detection system such as vacuum ultraviolet spectroscopy is therefore of great interest. Almost all molecules absorb the vacuum ultraviolet radiation and have distinct spectral features with compound classes exhibiting spectral signature similarities. Spectral information can be ‘filtered’ to extract the response in the most informative spectral ranges. Developed algorithms allow spectral mixture estimation of coeluting species. Vacuum ultraviolet detector follows Beer–Lambert law, with the possibility of calibrationless quantitation. The purpose of this article is to provide an overview of the features and specificities of gas chromatography–vacuum ultraviolet spectroscopy coupling which has gained interest since the recent introduction of a commercial vacuum ultraviolet detector. Potentials and limitations, relevant theoretical considerations, recent advances and applications are explored.     

气相色谱固定相研究新进展

发展高选择性固定相是实现气相色谱(GC)高效分离样品组分及其分析测定的关键。近年,材料科学的快速发展促进了新型色谱固定相的研究和应用。该文综述了近5年有关多孔材料、石墨烯及类似物、三聚茚类材料和蝶烯类材料等作为GC固定相的研究进展,并对GC固定相研究进行了总结和展望。     

Using computer modeling to predict and optimize separations for comprehensive two-dimensional gas chromatography

In order to fully realize the separation power of comprehensive two-dimensional gas chromatography (GC x GC), a means of predicting and optimizing separations based on operating variables was developed. This approach initially calculates the enthalpy (DeltaH) and entropy (DeltaS) for the target compounds from experimental input data, and then uses this information to simultaneously optimize all column and runtime variables, including stationary phase composition, by comparing the performance of large numbers of simulated separations. This use of computer simulation has been shown to be a useful aid in conventional separations. It becomes almost essential for GC x GC optimization because of the large number of variables involved and their very complex interaction. Agreement between experimental and predicted values of standard test samples (Grob mix) using GC x GC separation shows that this approach is accurate. We believe that this success can be extended to more challenging mixtures resulting in optimizations that are simpler and transferable between GC x GC instruments.     

生物制药研究中的多维色谱

对全二维气相色谱(GC×GC)、全二维液相色谱(HPLC×HPLC)、多维毛细管电泳等多维分离技术在生物制药研究中的应用进行了综述,其中对作者所在研究组在全二维气相色谱应用于中药及固相萃取-液相色谱联用分析系统等方面的工作做了重点介绍。由所综述的生物制药研究得出结论：多维分离方法以其高分辨、快速、自动化等特点已经在生物制药领域显示出它的巨大优势,并将发挥更大的作用。     

Recent applications of gas chromatography with high‐resolution mass spectrometry

Gas chromatography coupled to high‐resolution mass spectrometry is a powerful analytical method that combines excellent separation power of gas chromatography with improved identification based on an accurate mass measurement. These features designate gas chromatography with high‐resolution mass spectrometry as the first choice for identification and structure elucidation of unknown volatile and semi‐volatile organic compounds. Gas chromatography with high‐resolution mass spectrometry quantitative analyses was previously focused on the determination of dioxins and related compounds using magnetic sector type analyzers, a standing requirement of many international standards. The introduction of a quadrupole high‐resolution time‐of‐flight mass analyzer broadened interest in this method and novel applications were developed, especially for multi‐target screening purposes. This review is focused on the development and the most interesting applications of gas chromatography coupled to high‐resolution mass spectrometry towards analysis of environmental matrices, biological fluids, and food safety since 2010. The main attention is paid to various approaches and applications of gas chromatography coupled to high‐resolution mass spectrometry for non‐target screening to identify contaminants and to characterize the chemical composition of environmental, food, and biological samples. The most interesting quantitative applications, where a significant contribution of gas chromatography with high‐resolution mass spectrometry over the currently used methods is expected, will be discussed as well.     

Comprehensive multi-dimensional liquid chromatographic separation in biomedical and pharmaceutical analysis: a review

'Multi-dimensional' liquid separations have a history almost as long as chromatography. In multi-dimensional chromatography the sample is subjected to more than one separation mechanism; each mechanism is considered an independent separation dimension. The separations can be carried out either offline via fraction collection, or directly coupled online. Early multi-dimensional separations using combinations of paper chromatography, electrophoresis and gels, in both planar and columnar modes are reviewed. Developments in HPLC have increased the number of measurable analytes in ever more complex matrices, and this has led to the concept of 'global metabolite profiling'. This review focuses on the theory and practice of modern 'comprehensive' multi-dimensional liquid chromatography when applied to biomedical and pharmaceutical analysis.     

Supercritical fluid extraction in plant essential and volatile oil analysis

The use of supercritical fluids, especially carbon dioxide, in the extraction of plant volatile components has increased during two last decades due to the expected advantages of the supercritical extraction process. Supercritical fluid extraction (SFE) is a rapid, selective and convenient method for sample preparation prior to the analysis of compounds in the volatile product of plant matrices. Also, SFE is a simple, inexpensive, fast, effective and virtually solvent-free sample pretreatment technique. This review provides a detailed and updated discussion of the developments, modes and applications of SFE in the isolation of essential oils from plant matrices. SFE is usually performed with pure or modified carbon dioxide, which facilitates off-line collection of extracts and on-line coupling with other analytical methods such as gas, liquid and supercritical fluid chromatography. In this review, we showed that a number of factors influence extraction yields, these being solubility of the solute in the fluid, diffusion through the matrix and collection process. Finally, SFE has been compared with conventional extraction methods in terms of selectivity, rapidity, cleanliness and possibility of manipulating the composition of the extract.     

Separation of Enantiomers and Control of Elution Order of β-Lactams by GC Using Cyclodextrin-Based Chiral Stationary Phases

Enantiomers of 19 racemic β-lactams, with 3 and 4-position substitutions, were separated using gas chromatography. Excellent results were achieved on derivatized cyclodextrin-based GC chiral stationary phases (CSPs). All 19 compounds were baseline separated, most with high resolution factors. The Chiraldex G-TA was found to be the most powerful CSP with the broadest enantioselectivity, while Chiraldex B-DM produced the fastest separations for most of the compounds assayed. Results obtained in this work suggest that GC can serve as a potential method for the enantiomeric separation of sufficiently volatile solid β-lactams.