熱導(dǎo)檢測器

 

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.

熱導(dǎo)檢測器（TCD）又稱熱導(dǎo)池或熱絲檢熱器，是氣相色譜法常用的一種檢測器。基于不同組分與載氣有不同的熱導(dǎo)率的原理而工作的熱傳導(dǎo)檢測器。敏感元件為熱絲，如鎢絲、鉑絲、錸絲，并由熱絲組成電橋。在通過恒定電流以后，鎢絲溫度升高，其熱量經(jīng)四周的載氣分子傳遞至池壁。當(dāng)被測組分與載氣一起進(jìn)入熱導(dǎo)池時(shí)，由于混合氣的熱導(dǎo)率與純載氣不同（通常是低于載氣的熱導(dǎo)率），鎢絲傳向池壁的熱量也發(fā)生變化，致使鎢絲溫度發(fā)生改變，其電阻也隨之改變，進(jìn)而使電橋輸出端產(chǎn)生不平衡電位而作為信號輸出。熱導(dǎo)檢測器是氣象色譜法中早出現(xiàn)和應(yīng)用廣的檢測器。

近年來，盡管在許多方面它已被更靈敏更專屬性的各種檢測器所取代，但是由于它具有結(jié)構(gòu)簡單，性能穩(wěn)定，靈敏度適宜，線性范圍寬，對各種能作色譜的物質(zhì)都有響應(yīng)，適合作微量分析（ppm級）。在分析測試在中，熱導(dǎo)檢測器不僅用于分析污染物，而且用于分析一些用其他檢測器無法檢測的無機(jī)氣體，如氫、氧、氮、一氧化碳、二氧化碳等。



同時(shí)供應(yīng)：氫火焰檢測器FID,電子捕獲檢測器ECD，氮磷檢測器DNP,火焰光度檢測器，雙火焰光度檢測器，氬離子檢測器，氧化鋯檢測器

 

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