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茅茅
第11楼2007/05/04
以下是我的翻译,供参考
Apparatus— A gas chromatograph consists of a carrier gas source, an injection port, column, detector, and recording device. The injection port, column, and detector are temperature-controlled. The typical carrier gas is helium, nitrogen, or hydrogen, depending on the column and detector in use. The gas is supplied from a high-pressure cylinder or high-purity gas generator and passes through suitable pressure-reducing valves and a flow meter to the injection port and column. Compounds to be chromatographed, either in solution or as gases, are injected into the gas stream at the injection port. Depending upon the configuration of the apparatus, the test mixture may be injected directly into the column or be vaporized in the injection port and mixed into the flowing carrier gas prior to entering the column.
仪器—一台气相色谱仪包括了载气源、进样口、色谱柱、检测器和记录设备。进样口、柱和检测器的设计是温控的。根据所用的色谱柱和检测器的性质可以选择不同的载气，典型的有氦气、氮气或氢气，高压钢瓶或高纯气体发生器产生的气体经由适配的减压阀和流量计后进入进样口和色谱柱，溶液或气体中的待测组分从进样口进入气流。根据仪器的设置，测试混合物可以选择直接注入色谱柱（气体状态），或是在进样口气化后，与载气混合一并进入色谱柱（溶液状态）。
Once in the column, compounds in the test mixture are separated by virtue of differences in their capacity factors, which in turn depend upon vapor pressure and degree of interaction with the stationary phase. The capacity factor, which governs resolution, retention times, and column efficiencies of components of the test mixture, is also temperature-dependent. The use of temperature-programmable column ovens takes advantage of this dependence to achieve efficient separation of compounds differing widely in vapor pressure.
当样品进入色谱柱后，混合试样中各组分由于容量因子的差异会被彼此分离开，分离程度取决于各组分蒸汽压和组分与固定相之间的相互作用。容量因子与柱温有关，决定分离度，保留时间和柱效。利用程序升温方式，可以快速有效分离蒸汽压差异较大的组分。
As resolved compounds emerge separately from the column, they pass through a differential detector, which responds to the amount of each compound present. The type of detector to be used depends upon the nature of the compounds to be analyzed and is specified in the individual monograph. Detectors are heated to prevent condensation of the eluting compounds.
Detector output is recorded as a function of time, producing a chromatogram, which consists of a series of peaks on a time axis. Each peak represents a compound in the vaporized test mixture, although some peaks may overlap. The elution time is a characteristic of an individual compound; and the instrument response, measured as peak area or peak height, is a function of the amount present.
经由色谱柱洗脱分离的组分从色谱柱流出后，进入特殊的检测器。根据流出组分的量，检测器产生不同的响应。我们可以根据待分析样品的性质和各论规定下选择不同类型的检测器， 检测器应预先加热防止洗脱组分的冷凝。
检测器输出端记录色谱图，以时间为轴，绘出一系列的色谱峰，虽然有时候一些峰会发生重叠，但一般情况下一个峰代表了气化试样中的一种组分。每种组分有其特有的洗脱时间，仪器的响应值，峰面积和峰高都与组分的量有关。