毛细管气相色谱热导检测器的设计与应用

The Thermal Conductivity Detector (TDC) for Temperature—Programmed Capillary Gas Chromatography

根据对负压下热导检测器(TCD)响应特性的研究,新设计并研制出适用于程序升温气相毛细管色谱的TCD及恒流系统。所研制TCD的最小等效池体积为1.3μl,几何尺寸为100μl。热丝敏感区内无死角,无气流突变。内径为0.2mm以上的毛细管柱可以直接与该TCD连接而不需用尾吹气。该检测器的动态线性范围为4个数量级,对丁烷的灵敏度为0.005%(v/v),响应速度≤0.1秒。所设计的毛细管进样装置。能在程序升温条件下保证流经毛细管的流量恒定,进样分流比恒定。因此解决了程升条件下毛细管色谱用TCD检测的定量问题。文中给出了应用实例,说明该检测器和整个系统的适用性。

The TCD was constructed and evaluated in temperature programmedcapillary gas chromatography.The effective cell volume is 1.3 μl;while its physical volume is 100μl.The detector was based on a study of the response characteristics of the TCD at reduced pres-sure.no dead corner no abrupt change of flow direction inside the detector cell.Capillary columnsof inner diameter≥0.25mm can couple directly with the detector without make—up gas.The de-tector response time is less than 0.1s,linear dynamic range is 4 orders of magnitude,and thelowest detection limit of concentration is about 0.005% (v/v) for butane.A simple configurationof capillary inlet system offers a constant carrier gas flow through the column in temperature-programmed operation.Practical examples were given.