Department of Chemistry, National Tsing Hua University, 101, Section 2, Kuang-Fu Rd., Hsinchu 30013, Taiwan.
Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, 101, Section 2, Kuang-Fu Rd., Hsinchu 30013, Taiwan.
Anal Chem. 2021 Feb 2;93(4):2424-2432. doi: 10.1021/acs.analchem.0c04369. Epub 2021 Jan 20.
The analysis of volatile organic compounds (VOCs) normally involves sample collection, sample transfer to laboratory, sample preparation, and the chromatographic separation of analytes. However, in some cases, it is impractical or impossible to collect samples prior to the analysis, while the analysis time has to be minimized. Ion mobility spectrometry (IMS) is an ideal technique for a rapid chemical analysis. Here, we present a portable cloud-integrated pen-probe analyzer based on IMS and demonstrate its applications in the analysis of VOCs emanating from surfaces. The user approaches the pen-probe to a sampled surface and presses a button on the pen-probe. The analysis is then executed automatically. The VOCs are scavenged from the surface by a suction force and directed to a corona discharge atmospheric pressure chemical ionization source. The ions are separated in a drift tube according to their size and charge and then detected by a Faraday plate detector. The detector signal is amplified and digitized. The spectral data are deposited in the Internet cloud along with time and location data for further retrieval and processing. The platform incorporates a mobile Wi-Fi router for easy connectivity and a global positioning system module for geolocation. The prototype was developed using low-cost electronic modules (Arduino, Tinker Board S). It was further characterized using chemical standards. The limits of detection for pyrrolidine, 2,4-lutidine, and (-)-nicotine are 48.9, 2.30, and 416 nmol, respectively (amounts of substances placed on the sampling surface). The selected real specimens (nicotine patch, skin exposed to nicotine, fish sauce, and fried chicken) were also subjected to analysis yielding the characteristic ion mobility spectra.
挥发性有机化合物（VOCs）的分析通常涉及样品采集、样品转移到实验室、样品制备以及分析物的色谱分离。然而，在某些情况下，在分析之前采集样品是不切实际或不可能的，而分析时间必须最小化。离子迁移谱（IMS）是一种快速化学分析的理想技术。在这里，我们展示了一种基于 IMS 的便携式云集成笔式探头分析仪，并演示了其在分析表面散发的 VOCs 中的应用。用户将笔式探头靠近采样表面并按下笔式探头的按钮。然后自动执行分析。通过吸力从表面中捕获 VOCs，并将其引导至电晕放电大气压化学电离源。离子根据其大小和电荷在漂移管中分离，然后用法拉第板检测器检测。检测器信号被放大和数字化。光谱数据与时间和位置数据一起存储在互联网云中，以便进一步检索和处理。该平台包含一个移动 Wi-Fi 路由器，便于连接，以及一个全球定位系统模块，用于地理定位。该原型使用低成本电子模块（Arduino、Tinker Board S）开发。它进一步使用化学标准进行了表征。吡咯烷、2,4-六氢吡啶和（-）尼古丁的检测限分别为 48.9、2.30 和 416 nmol（置于采样表面上的物质量）。还对选定的实际标本（尼古丁贴片、暴露于尼古丁的皮肤、鱼露和炸鸡）进行了分析，得到了特征离子迁移谱。
