Surface & Microanalysis Science Division, National Institute of Standards and Technology, MS-8371, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States.
Anal Chem. 2013 Mar 5;85(5):2652-8. doi: 10.1021/ac302944m. Epub 2013 Feb 12.
Ion mobility spectrometers have found widespread use for the screening of explosives, chemical warfare agents, and illicit drugs. These instruments often rely on drift-time calibrants to perform qualitative identification. Such calibrants are suitable to determine the reduced mobility of compounds, but may not necessarily provide information on instrument performance. These calibrants are often internal and behave in a fashion similar to that of analytes in terms of sensitivity to a variety of instrumental and environmental variations. Ideally, test materials used to evaluate instrument performance would be insensitive to these changes. Current calibrants are sometimes not designed to satisfy these requirements, and although several instrument test materials are also in use, a consensus has not been reached on best practices. A homologous series of tetraalkylammonium salts has been proposed as one alternative instrumental test material set and has been successfully used for electrospray ion mobility spectrometry (IMS)-MS experiments. This study extends these analyses to thermal desorption IMS instruments. The reduced mobility (K0) values for these compounds, measured on a thermal desorption IMS instrument, are reported and are similar to those reported for electrospray IMS. The variability of daily instrument response to these compounds is small, further supporting their use as test materials. The ionization behavior and thermal profile of the compounds in the thermal desorption process are discussed.
离子淌度谱仪已广泛应用于爆炸物、化学战剂和非法药物的筛选。这些仪器通常依赖漂移时间校准剂来进行定性鉴定。此类校准剂适用于确定化合物的迁移率，但不一定能提供有关仪器性能的信息。这些校准剂通常是内部的，并且在对各种仪器和环境变化的敏感性方面与分析物的行为相似。理想情况下，用于评估仪器性能的测试材料不应受这些变化的影响。目前的校准剂有时无法满足这些要求，尽管也在使用几种仪器测试材料，但尚未就最佳实践达成共识。已提出一系列四烷基铵盐作为一种替代仪器测试材料，并已成功用于电喷雾离子淌度谱（IMS）-MS 实验。本研究将这些分析扩展到热解吸 IMS 仪器。报告了这些化合物在热解吸 IMS 仪器上的迁移率（K0）值，与电喷雾 IMS 报告的值相似。这些化合物每天对仪器响应的变化很小，进一步支持将它们用作测试材料。讨论了化合物在热解吸过程中的电离行为和热谱。
