Chapter 16-Gas Chromatography

气相色谱的使用流程英文回答：Gas Chromatography Procedure.Gas chromatography (GC) is a separation technique used to analyze complex mixtures of volatile compounds. It is based on the principle that different compounds have different affinities for a stationary phase, and thus travel through the column at different rates.Materials:Gas chromatograph.Column.Carrier gas.Sample.Syringe or autosampler.Procedure:1. Prepare the sample. The sample should be dissolved in a volatile solvent and filtered to remove anyparticulate matter.2. Select the column. The column is a long, narrow tube that is coated with a stationary phase. The stationary phase is typically a liquid or solid that has a highaffinity for the compounds being analyzed.3. Set the carrier gas flow rate. The carrier gas is used to move the sample through the column. The flow rateis typically set to between 1 and 10 mL/min.4. Inject the sample. The sample is injected into the column using a syringe or autosampler.5. Separate the compounds. The compounds in the sampletravel through the column at different rates, based ontheir affinity for the stationary phase.6. Detect the compounds. The compounds are detected as they elute from the column. There are a variety of detectors that can be used, including flame ionization detectors (FIDs), mass spectrometers (MSs), and electron capture detectors (ECDs).7. Analyze the data. The data from the detector is used to identify and quantify the compounds in the sample.Troubleshooting:If the compounds are not eluting from the column, the carrier gas flow rate may be too low or the column may be too long.If the peaks are too wide, the column may be too short or the carrier gas flow rate may be too high.If the peaks are not symmetrical, the sample may notbe dissolved in a volatile solvent or the column may be contaminated.中文回答：气相色谱操作流程。

色谱柱英文缩写色谱柱是气相色谱、液相色谱、毛细管电泳等色谱分析技术中重要的组成部分，它的选择会直接影响到实验结果的准确性和分辨率。

在科学研究和实验操作中，经常需要用到色谱柱的英文缩写，以下是常见的几种：1. GC：Gas Chromatography，气相色谱柱2. HPLC：High Performance Liquid Chromatography，高效液相色谱柱3. LC：Liquid Chromatography，液相色谱柱4. CE：Capillary Electrophoresis，毛细管电泳柱5. SEC：Size Exclusion Chromatography，分子筛色谱柱6. RP：Reverse Phase Chromatography，反相色谱柱7. IC：Ion Chromatography，离子色谱柱8. GPC：Gel Permeation Chromatography，凝胶渗透色谱柱9. NP：Normal Phase Chromatography，正相色谱柱10. SCX：Strong Cation Exchange，强阳离子交换色谱柱11. SAX：Strong Anion Exchange，强阴离子交换色谱柱12. WCX：Weak Cation Exchange，弱阳离子交换色谱柱13. WAX：Weak Anion Exchange，弱阴离子交换色谱柱14. C18：Octadecylsilane，十八烷基硅烷色谱柱15. C8：Octylsilane，八烷基硅烷色谱柱16. CN：Cyano，氰基色谱柱17. NH2：Amino，氨基色谱柱18. Diol：Diol，双羟基色谱柱通过掌握这些色谱柱的英文缩写，可以更方便地理解和使用相关研究论文或实验操作指南，并且在相关领域的交流与合作中也能更加顺畅。

1、气相色谱法（GC）—gas chromatography用气体做为流动相的色法。

2、气液色谱法（GLC）—gas liquid chromatography 将固定液涂在载体上作为固定相的气相色谱法。

3、气固色谱法（GSC）—gas solid chromatography 用固体（一般指吸附剂）作固定相的气相色谱法。

4、程序升温气相色谱法—programmed temperature gas chromatography 色谱柱按照预定的程序连续地或分阶段地进升温的气相色谱法。

5、反应气相色谱法—reaction gas chromatography 试样以过色谱前、后的反应区进行化学反应的气相色谱法。

6、裂解气相色谱法—pyrolysis gas chromatography 试样经过高温、激光、电弧等途径，裂解为较小分子后进入色谱柱的气相色谱法。

7、顶空报相色谱法—haed （应为head -编者注）space gas chromatography d在密闭的容器中与液体（或）固体）试样处于势力学平衡（应为热力学平衡 -编者注）状态的气相组分，是间接测定试样中挥发性组分的一种方法。

8、毛细管气相色谱法—capillary gas chromatography 使用具有高分离效能的毛细管柱的气相色谱法。

9、多维气相色谱法—multidimensional gas chromatography 将两个或多个色谱柱组合，通过切换，可进行正吹、反吹或切割等的气相色谱法。

10、制备气相色谱法—preparative gas chromatography 用能处理较大量试样的色谱系统，进行分离、切割和收集组分，以提纯化全物的气相色谱法。

11、色谱柱：chromatographic column内有固定相用以分离混合组分的柱管。

12、填充柱：packed cklumn （应为column-编者注）填充了固定相的色谱柱。

气相色谱恒温英文英文回答：Gas chromatography (GC) is a separation technique used to analyze the volatile components of a sample. It is based on the principle that different compounds have different affinities for a stationary phase and a mobile phase. The sample is injected into a heated column that contains a stationary phase. The mobile phase, which is a carrier gas, flows through the column and carries the sample components along with it. The different compounds in the sample will interact with the stationary phase to varying degrees, causing them to elute from the column at different times.The elution time of a compound is determined by its boiling point, its polarity, and its molecular weight. Compounds with lower boiling points will elute from the column first, followed by compounds with higher boiling points. Polar compounds will interact more strongly with the stationary phase than nonpolar compounds, and they willtherefore elute later. Heavier compounds will also interact more strongly with the stationary phase than lighter compounds, and they will therefore elute later.The elution of the sample components is detected by a detector, which is located at the end of the column. The detector generates a signal that is proportional to the concentration of the compound in the mobile phase. Thesignal from the detector is recorded on a chromatogram, which is a graph of the detector signal versus time.GC is a powerful analytical technique that can be usedto identify and quantify the components of a sample. It is widely used in a variety of applications, including environmental analysis, food analysis, and pharmaceutical analysis.中文回答：气相色谱（GC）是一种用于分析样品中挥发性成分的分离技术。

气相色谱死时间气相色谱（Gas Chromatography，GC）是一种常用的分离和分析技术。

它利用样品在固定相耦合之气相流动中的物理化学性质差异，通过在固定相中的滞留时间的差异实现对混合物的分离，并进一步利用检测器测定各组分的相对含量。

气相色谱的基本原理是：利用携带样品的气相流动经由色谱柱的固定相区分离各组分，当进样量、流速、柱温等实验条件一定时，样品中的各成分将在某一特定时间点出现在色谱图上，并以各组分峰面积或峰高的相对大小表征各组分的相对含量。

死时间是指流速使挥发性物质或溶剂的运移时间，死时间不同于滞留时间，滞留时间是指要检测物质从进样口到检测器所需时间。

气相色谱的死时间是一个重要的参数，它与柱长度、内径、流速等因素有关。

为了准确衡量样品中各组分的沉降时间，需要减去死时间的影响。

一般来说，死时间是通过注入一种可以方便测得滞留时间的物质（例如烷烃、醇类等）来进行测定的。

在气相色谱中，死时间的测定可使用不同的方法，主要有外标法、内标法、分离前注射法和内标萃取法等。

其中，外标法是指在样品中添加一个已知浓度的标准物质，通过比较它们的峰面积或峰高来确定死时间；内标法是指在样品中添加一个已知浓度的内标物质，通过比较它们的峰面积或峰高来确定死时间；分离前注射法是利用一个具有恒定死时间的小溶剂蒸气回收装置，将蒸馏后的小溶剂蒸气与样品一起通过柱子，在峰面积一次升高的最高峰位置之前注射另一个样品试管中的未插入样品；内标萃取法通过在样品中添加一个内标物质，萃取并分析，从而求得样品中各组分的死时间。

气相色谱的死时间不仅仅是检测技术中的一个参数，更是色谱分析方法中样品分析的基础。

在分析复杂的样品时，由于样品中可能同时存在多种组分，这些组分在固定相中的滞留时间可能会有很大的差异，因此必须准确测定死时间，才能确定各组分的真正滞留时间，从而正确分析并计算样品中各组分的含量。

同时，死时间还可以用来评价柱子性能的稳定性，它可以描述柱子的保留能力、分离能力和抗污染性等。

《仪器分析》（双语）课程教学大纲 （中文）仪器分析（双语） 课程编号 11445003 课程名称（英文）Instrumental Analysis (Double Language)课程基本情况1．学分credit ：5 学时class hour ：50 hr (课内学时：45hr 实验学时： 5hr)2．课程性质： 学科基础课 Fundamental course of the subject3．适用专业：环境科学与工程，化学工程 (Environmental or Chemical Engineering) 适用对象：本科生 (Undergraduate student)4．先修课程：分析化学Chemical Analysis 、物理化学Physical Chemistry5．首选教材：Instrumental Analysis (原版，摘编)二选教材：朱明华，《仪器分析》，第三版，高等教育出版社， 2000年参考书目：1、Skoog,.A., Principles of Instrumental Analysis, Saunders CollegePublishing, 5th Ed., 1998。

2、Willard,H.H., et al., Instrumental Methods ofAnalysis, Wasworth Publishing Company, 6th Ed. 1981;6．考核形式：考试（笔试，开卷，英语试卷）Examination (Written, English test paper, Open book)7．教学环境：以多媒体课堂教学为主 (Primarily consist of lecture in-class withmultimedia form)课程教学目的及要求 教学目的：仪器分析是环境与化工学院各专业本科生的一门专业基础课，本课程主要讲授用于化学分析的各种现代仪器分析方法(包括：光谱，色谱和电化学等方法)的原理和应用技术。

气相色谱法英文缩写气相色谱法（GasChromatography，简称GC），也称气相析出法，是分析化学实验中最为重要的方法之一。

它是一种以色谱技术进行分离和分析的分析方法，是当今工业上最常用的技术之一。

这种技术的应用范围很广，可以用于研究化合物的结构和稳定性，也可以用于分类，分析，鉴定，精确测定化合物的成分，以及分析有机类或无机类物质中的混合物等。

气相色谱法的原理是在一定温度和压力下，分子在柱内向前游离，离子形式的分子被磷酸根或其它有电荷的汽相溶剂的吸附，而无电荷的分子直接进入柱，根据柱内不同的分子在柱内的被运移速率，分子被运移成离子形式或原子形式，因此，分子以及其组成成分之间的结构（如等电点，质量数量率）和分子大小之间的结构，可以在柱内分离开来。

实验装置可以根据实验方法和要求，选择不同的汽相溶剂和柱，使柱内的活性层有所改变，以改变分子的活性。

实验过程中，柱内分子向前游离，分子的运移速率受到柱的影响，在柱的出口端，有专用的检测器，可以检测柱内游离的分子，从而可以检测出分子的特性，进而检测出混合物中各种分子组成成分的含量。

在实验中，检测仪通过对柱出口端的分子流进行测量和分析，以获得有关分子的信息，这种信息可以帮助我们了解混合物的组成成分的含量，以及各种物质的组成成分。

另外，气相色谱法还可以用来检测物质的精细性能，如粘合、挥发、溶解性等。

气相色谱法是当今化学实验中最重要的一种分析方法，具有重要的应用价值。

气相色谱法的实验室设计要求相对复杂，实验装置较为复杂，选择和使用柱，需要根据实验目的和要求进行选择。

在实验中，操作者需要了解柱的类型，以及操作过程中的温度、压力、流量等参数的要求，以及检测器的运行原理。

气相色谱法的优点是实验装置简单，实验方法十分简便，实验时间短，而且它可以检测到极小的量，精度高，分离准确，广泛应用于化学实验中，可用于研究物质的组成，可以准确测定混合物中各种成份的含量，只要有合适的实验条件，就能准确分析出混合物中各种成份的含量。

IntroductionGas chromatography - specifically gas-liquid chromatography - involves a sample being vapourised and injected onto the head of the chromatographic column. The sample is transported through the column by the flow of inert, gaseous mobile phase. The column itself contains a liquid stationary phase which is adsorbed onto the surface of an inert solid.Have a look at this schematic diagram of a gas chromatograph:Instrumental componentsCarrier gasThe carrier gas must be chemically inert. Commonly used gases include nitrogen, helium, argon, and carbon dioxide. The choice of carrier gas is often dependant upon the type of detector which is used. The carrier gas system also contains a molecular sieve to remove water and other impurities.Sample injection portFor optimum column efficiency, the sample should not be too large, and should be introduced onto the column as a "plug" of vapour - slow injection of large samples causes band broadening and loss of resolution. The most common injection method is where a microsyringe is used to inject samplethrough a rubber septum into a flash vapouriser port at the head of the column. The temperature of the sample port is usually about 50︒C higher than the boiling point of the least volatile component of the sample. For packed columns, sample size ranges from tenths of a microliter up to 20 microliters. Capillary columns, on the other hand, need much less sample, typically around 10-3μL. For capillary GC, split/splitless injection is used. Have a look at this diagram of a split/splitless injector;The injector can be used in one of two modes; split or splitless. The injector contains a heated chamber containing a glass liner into which the sample is injected through the septum. The carrier gas enters the chamber and can leave by three routes (when the injector is in split mode). The sample vapourises to form a mixture of carrier gas, vapourised solvent and vapourised solutes. A proportion of this mixture passes onto the column, but most exits through the split outlet. The septum purge outlet prevents septum bleed components from entering the column.ColumnsThere are two general types of column, packed and capillary (also known as open tubular). Packed columns contain a finely divided, inert, solid support material (commonly based on diatomaceous earth) coated withliquid stationary phase. Most packed columns are 1.5 - 10m in length and have an internal diameter of 2 - 4mm.Capillary columns have an internal diameter of a few tenths of a millimeter. They can be one of two types; wall-coated open tubular (WCOT)or support-coated open tubular (SCOT). Wall-coated columns consist of a capillary tube whose walls are coated with liquid stationary phase. In support-coated columns, the inner wall of the capillary is lined with a thin layer of support material such as diatomaceous earth, onto which the stationary phase has been adsorbed. SCOT columns are generally less efficient than WCOT columns. Both types of capillary column are more efficient than packed columns.In 1979, a new type of WCOT column was devised - the Fused Silica Open Tubular (FSOT) column;These have much thinner walls than the glass capillary columns, and are given strength by the polyimide coating. These columns are flexible and can be wound into coils. They have the advantages of physical strength, flexibility and low reactivity.Column temperatureFor precise work, column temperature must be controlled to within tenths of a degree. The optimum column temperature is dependant upon the boiling point of the sample. As a rule of thumb, a temperature slightly above the average boiling point of the sample results in an elution time of 2 - 30 minutes. Minimal temperatures give good resolution, but increase elution times. If a sample has a wide boiling range, then temperature programming can be useful. The column temperature is increased (either continuously or in steps) as separation proceeds.DetectorsThere are many detectors which can be used in gas chromatography. Different detectors will give different types of selectivity.A non-selective detector responds to all compounds except the carrier gas, a selective detector responds to a range of compounds with a common physical or chemical property and a specific detector responds to a single chemical compound. Detectors can also be grouped into concentration dependant detectors and mass flow dependant detectors. The signal from a concentration dependant detector is related to the concentration of solute in the detector, and does not usually destroy the sample Dilution of with make-up gas will lower the detectors response. Mass flow dependant detectors usually destroy the sample, and the signal is related to the rate at which solute molecules enter the detector. The response of a mass flow dependant detector is unaffected by make-up gas. Have a look at this tabular summary of common GC detectors:Review your learningBiosciences Homepage。