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气相色谱原理浅析

<p><span style="color: #333333; font-family: 'PingFang SC', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', STHeiti, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', 'Helvetica Neue', 'Microsoft Yahei', sans-serif; font-size: 16px; letter-spacing: 0.4px; background-color: #ffffff;">气相色谱原理与分馏类似。它们都主要利用混合物中各个组分的沸点(或蒸气压)的差异对混合物中的各个组分进行分离。但是,分馏通常用于常量的混合物的分离,而气相色谱所分离的物质则要少得多(微量)。</span></p> <p style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-variant-alternates: inherit; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: 'PingFang SC', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', STHeiti, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', 'Helvetica Neue', 'Microsoft Yahei', sans-serif; font-optical-sizing: inherit; font-kerning: inherit; font-feature-settings: inherit; font-variation-settings: inherit; vertical-align: baseline; color: #333333; letter-spacing: 0.4px; background-color: #ffffff;"> </p> <p style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-variant-alternates: inherit; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: 'PingFang SC', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', STHeiti, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', 'Helvetica Neue', 'Microsoft Yahei', sans-serif; font-optical-sizing: inherit; font-kerning: inherit; font-feature-settings: inherit; font-variation-settings: inherit; vertical-align: baseline; color: #333333; letter-spacing: 0.4px; background-color: #ffffff;">气相色谱中的流动相(或活动相)是载气,通常使用惰性气体(如氦气)或反应性差的气体(如氮气)。固定相则由一薄层液体或聚合物附着在一层惰性的固体载体表面构成。固定相装在由玻璃或金属制成的一根空心管柱内(称为色谱柱)。用作进行气相色谱的仪器称为气相色谱仪(或“气体分离器”)。</p> <p style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-variant-alternates: inherit; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: 'PingFang SC', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', STHeiti, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', 'Helvetica Neue', 'Microsoft Yahei', sans-serif; font-optical-sizing: inherit; font-kerning: inherit; font-feature-settings: inherit; font-variation-settings: inherit; vertical-align: baseline; color: #333333; letter-spacing: 0.4px; background-color: #ffffff;"> </p> <p style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-variant-alternates: inherit; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: 'PingFang SC', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', STHeiti, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', 'Helvetica Neue', 'Microsoft Yahei', sans-serif; font-optical-sizing: inherit; font-kerning: inherit; font-feature-settings: inherit; font-variation-settings: inherit; vertical-align: baseline; color: #333333; letter-spacing: 0.4px; background-color: #ffffff;">待分析的气体样品与覆盖有各种各样的固定相的柱壁相互作用,使得不同的物质在不同的时间被洗脱出来。从一种物质进样开始到出现色谱峰最大值的时间被称为该物质的保留时间,通过将未知物质的保留时间与相同条件下标准物质的保留时间的比较可以表征未知物。</p> <p style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-variant-alternates: inherit; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: 'PingFang SC', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', STHeiti, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', 'Helvetica Neue', 'Microsoft Yahei', sans-serif; font-optical-sizing: inherit; font-kerning: inherit; font-feature-settings: inherit; font-variation-settings: inherit; vertical-align: baseline; color: #333333; letter-spacing: 0.4px; background-color: #ffffff;"> </p> <p style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-variant-alternates: inherit; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: 'PingFang SC', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', STHeiti, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', 'Helvetica Neue', 'Microsoft Yahei', sans-serif; font-optical-sizing: inherit; font-kerning: inherit; font-feature-settings: inherit; font-variation-settings: inherit; vertical-align: baseline; color: #333333; letter-spacing: 0.4px; background-color: #ffffff;">拓展资料:</p> <p style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-variant-alternates: inherit; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: 'PingFang SC', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', STHeiti, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', 'Helvetica Neue', 'Microsoft Yahei', sans-serif; font-optical-sizing: inherit; font-kerning: inherit; font-feature-settings: inherit; font-variation-settings: inherit; vertical-align: baseline; color: #333333; letter-spacing: 0.4px; background-color: #ffffff;"> </p> <p style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-variant-alternates: inherit; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: 'PingFang SC', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', STHeiti, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', 'Helvetica Neue', 'Microsoft Yahei', sans-serif; font-optical-sizing: inherit; font-kerning: inherit; font-feature-settings: inherit; font-variation-settings: inherit; vertical-align: baseline; color: #333333; letter-spacing: 0.4px; background-color: #ffffff;"><strong><a title="气相色谱仪" href="https://www.kexingtest.com/instrument/detail?id=161" target="_blank" rel="noopener">气相色谱仪</a></strong>是用于分离复杂样品中的化合物的化学分析仪器。气相色谱仪中有一根流通型的狭长管道,这就是色谱柱。在色谱柱中,不同的样品因为具有不同的物理和化学性质,与特定的柱填充物(固定相)有着不同的相互作用而被气流(载气,流动相)以不同的速率带动。当化合物从柱的末端流出时,它们被检测器检测到,产生相应的信号,并被转化为电信号输出。在色谱柱中固定相的作用是分离不同的组分,使得不同的组分在不同的时间(保留时间)从柱的末端流出。其它影响物质流出柱的顺序及保留时间的因素包括载气的流速,温度等。</p> <p style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-variant-alternates: inherit; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: 'PingFang SC', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', STHeiti, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', 'Helvetica Neue', 'Microsoft Yahei', sans-serif; font-optical-sizing: inherit; font-kerning: inherit; font-feature-settings: inherit; font-variation-settings: inherit; vertical-align: baseline; color: #333333; letter-spacing: 0.4px; background-color: #ffffff;"> </p> <p style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-variant-alternates: inherit; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: 'PingFang SC', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', STHeiti, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', 'Helvetica Neue', 'Microsoft Yahei', sans-serif; font-optical-sizing: inherit; font-kerning: inherit; font-feature-settings: inherit; font-variation-settings: inherit; vertical-align: baseline; color: #333333; letter-spacing: 0.4px; background-color: #ffffff;">在气相色谱分析法中,一定量(已知量)的气体或液体分析物被注入到柱一端的进样口中(通常使用微量进样器,也可以使用固相微萃取纤维(solid phase microextraction fibres)或气源切换装置)。当分析物在载气带动下通过色谱柱时,分析物的分子会受到柱壁或柱中填料的吸附,使通过柱的速度降低。分子通过色谱柱的速率取决于吸附的强度,它由被分析物分子的种类与固定相的类型决定。由于每一种类型的分子都有自己的通过速率,分析物中的各种不同组分就会在不同的时间(保留时间)到达柱的末端,从而得到分离。检测器用于检测柱的流出流,从而确定每一个组分到达色谱柱末端的时间以及每一个组分的含量。通常来说,人们通过物质流出柱(被洗脱)的顺序和它们在柱中的保留时间来表征不同的物质。</p> <p style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-variant-alternates: inherit; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: 'PingFang SC', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', STHeiti, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', 'Helvetica Neue', 'Microsoft Yahei', sans-serif; font-optical-sizing: inherit; font-kerning: inherit; font-feature-settings: inherit; font-variation-settings: inherit; vertical-align: baseline; color: #333333; letter-spacing: 0.4px; background-color: #ffffff;"> </p> <p style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-variant-alternates: inherit; font-stretch: inherit; font-size: 16px; line-height: inherit; font-family: 'PingFang SC', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', STHeiti, Oxygen, Ubuntu, Cantarell, 'Fira Sans', 'Droid Sans', 'Helvetica Neue', 'Microsoft Yahei', sans-serif; font-optical-sizing: inherit; font-kerning: inherit; font-feature-settings: inherit; font-variation-settings: inherit; vertical-align: baseline; color: #333333; letter-spacing: 0.4px; background-color: #ffffff;"> </p>