Han Hai-yan, Jia Xian-de, Huang Guo-dong, Wang Hong-mei, Li Jian-quan, Jin Shun-ping, Jiang Hai-he, Chu Yan-nan, Zhou Shi-kang
Laboratory of Environmental Spectroscopy, Anhui Institute of Optics and Fine Mechanics, Key Laboratory of Environmental Optics and Technology, Chinese Academy of Sciences, Hefei 230031, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2007 Oct;27(10):1925-8.
Ion mobility spectrometry (IMS) is based on determining the drift velocities, which the ionized sample molecules attain in the weak electric field of a drift tube at atmospheric pressure. The drift behavior can be affected by structural differences of the analytes, so that ion mobility spectrometry has the ability to separated isomeric compounds. In the present article, an introduction to IMS is given, followed by a description of the instrument used for the experiments to differentiate isomeric compounds. Positive ion mobility spectras of three kinds of isomeric volatile organic compounds were studied in a homemade high-resolution IMS apparatus with a discharge ionization source. The study includes the differences in the structure of carbon chain, the style of function group, and the position of function group. The reduced mobility values were determined, which are in very good agreement with the previously reported theoretical values using neural network theory. The influence of the structural features of the substances and including the size and shape of the molecule has been investigated. The reduced mobility values increases in the order: alcohols < acetones < aromas, linears < branches < cycles, and para- < meta- < ortho-. The deviating ion mobility spectra of the constitutional isomers studied reflect the influence of structural features. In order to calibrate or determine the detection limits and the sensitivity of the ion mobility spectrometry, the exponential dilution flask (EDF) was used. Using this method, the detection limit of the analytes can reach the order of magnitude of ng x L(-1).
离子迁移谱（IMS）基于测定离子化的样品分子在大气压下漂移管的弱电场中所达到的漂移速度。漂移行为会受到分析物结构差异的影响，因此离子迁移谱有能力分离同分异构体化合物。在本文中，首先介绍了离子迁移谱，接着描述了用于区分同分异构体化合物实验的仪器。在一台配备放电电离源的自制高分辨率离子迁移谱仪上研究了三种同分异构挥发性有机化合物的正离子迁移谱。该研究包括碳链结构、官能团类型以及官能团位置的差异。测定了折合迁移率值，其与先前使用神经网络理论报道的理论值非常吻合。研究了物质结构特征（包括分子大小和形状）的影响。折合迁移率值按以下顺序增加：醇类＜丙酮类＜芳烃类，直链＜支链＜环状，对位＜间位＜邻位。所研究的同分异构体质的偏离离子迁移谱反映了结构特征的影响。为了校准或确定离子迁移谱的检测限和灵敏度，使用了指数稀释瓶（EDF）。采用这种方法，分析物的检测限可达到纳克×升⁻¹数量级。
