用于离子迁移率谱仪的快速热解析进样方法

摘要

The thermal desorption is an important method for the introduction of liquid and solid samples into an ion mobility spectrometer (IMS). There are the problems of recondensation or decomposition for detecting low-volatile or thermally unstable organic compounds. A rapid thermal desorption device coupled with IMS membrane was developed. A micro-heater and a thermocouple were used to control the temperature of desorption for improving the efficiency of sample introduction. The experiments were carried out for the detection of low-concentration melamine solution. The effect of heating parameters on IMS product ion peak was investigated. The results show that the sample can be concentrated and sample loss and pollution can be reduced by using a temperature controlled heater with a heating rate of 76 ℃/s up to the 230 ℃ which ensures the linear response and low limit of detection (lower than 0. 05 ng).%热解析是用于离子迁移率谱仪(IMS)的液体和固体样品进样的重要手段,但在检测高沸点或易分解有机物时,存在易重新凝结或过热分解的问题.本研究建立了一种与IMS半透膜结合的热解析进样方法,设计了可快速加热的微型热解析装置,通过热子通电发热及热电偶测温实现对样品解析区域的升温控制,提高半透膜的进样效率.以低浓度三聚氰胺溶液为例进行了检测实验,分析了解析装置的加热特性及不同温度和升温速度下的IMS产物离子峰变化.结果表明,采用升温速率为76℃/s的脉冲加热至230℃的热解析方法,样品释放集中,通过半透膜时损失和污染少,保证了输出线性和较低的检出限(低于0.05 ng).