热导检测器

 

Thermal conductivity detector (TCD), also known as thermal conductivity of the pool or hot wire, is the most commonly used gas chromatography a detector. A thermal conductivity detector operating on the principle that the different components have different thermal conductivities from the carrier gas. Sensitive components for the hot wire, such as tungsten wire, platinum wire, rhenium wire, and the composition of the bridge by the hot wire. After a constant current, the temperature of the tungsten filament is increased, and the heat is transferred to the cell wall by the carrier gas around it. When the measured component and the carrier gas into the thermal conductivity pool, the mixed gas thermal conductivity and pure carrier gas is different (usually lower than the thermal conductivity of the carrier gas), tungsten wire to the wall of the heat also occurred Change, resulting in tungsten wire temperature changes, the resistance also will change, and then make the bridge output unbalanced potential and as a signal output. Thermal conductivity detector is the first appearance of gas chromatography and the most widely used detector. In recent years, although in many ways it has been more sensitive and more specific detector replaced, but because it has a simple structure, stable performance, sensitivity, suitable for a wide linear range for a variety of substances can have chromatography Response, the most suitable for microanalysis (ppm level). In the analytical test, the thermal conductivity detector is not only used for the analysis of organic pollutants, but also for the analysis of some other detectors can not detect inorganic gases such as hydrogen, oxygen, nitrogen, carbon monoxide, carbon dioxide and so on.

热导检测器（TCD）又称热导池或热丝检热器，是气相色谱法最常用的一种检测器。基于不同组分与载气有不同的热导率的原理而工作的热传导检测器。敏感元件为热丝，如钨丝、铂丝、铼丝，并由热丝组成电桥。在通过恒定电流以后，钨丝温度升高，其热量经四周的载气分子传递至池壁。当被测组分与载气一起进入热导池时，由于混合气的热导率与纯载气不同（通常是低于载气的热导率），钨丝传向池壁的热量也发生变化，致使钨丝温度发生改变，其电阻也随之改变，进而使电桥输出端产生不平衡电位而作为信号输出。热导检测器是气象色谱法中最早出现和应用最广的检测器。

近年来，尽管在许多方面它已被更灵敏更专属性的各种检测器所取代，但是由于它具有结构简单，性能稳定，灵敏度适宜，线性范围宽，对各种能作色谱的物质都有响应，最适合作微量分析（ppm级）。在分析测试在中，热导检测器不仅用于分析有机污染物，而且用于分析一些用其他检测器无法检测的无机气体，如氢、氧、氮、一氧化碳、二氧化碳等。



同时供应：氢火焰检测器FID,电子捕获检测器ECD，氮磷检测器DNP,火焰光度检测器，双火焰光度检测器，氩离子检测器，氧化锆检测器