Fundamentals, Development and Applications of Ion Mobility Spectrometry (IMS) for Enhanced Trace Detection of Threat Agents

我们社会的全球化意味着，在国土安全方面，越来越需要可靠、实时和敏感地探测对我们社会构成威胁的各种物质。要检测的化学品范围从爆炸物到非法麻醉品以及化学和生物制剂。快速准确地测量这些有害化合物，并将它们从复杂的化学环境中区分出来的能力，对于我们国家打击犯罪和恐怖主义的需要至关重要。用于此类安全的常用设备通常基于离子迁移谱法（IMS），并且通常用于筛选人员或物体。如果你在机场检查你的笔记本电脑是否有爆炸物的痕迹，或者如果你走过一个哨兵，用来检查人们是否有爆炸物或麻醉品的痕迹，你可能经历过它的应用。然而，IMS不仅用于运输安全，而且还用于军事和民用设施。IMS通过产生带正电荷或带负电荷的带电分子（离子）来运行。这些离子在电场的影响下以平均恒定速度迁移并与中性分子碰撞。碰撞和反应（离子-分子反应）导致其他离子种类的形成，这些离子种类可能与微量气体反应。当离子沿着电场前进时，所产生的迁移率的变化被监测和处理，以试图识别存在的任何威胁材料。目前部署的IMS系统有许多限制，包括灵敏度和选择性，这导致该技术没有得到充分利用。主要的限制是化学特异性低，限制了易于检测的化合物类型。许多爆炸物和化学威胁是无法探测到的。为了克服这一点，需要一种新颖的科学方法，采用详细的基础和分阶段研究计划来了解IMS中使用的关键化学过程，特别是在英国沃特福德史密斯检测有限公司开发的最新一代漂移管系统中发生的化学过程。需要进行系统的研究，研究电离化学，化学掺杂剂的使用（改变化学）和操作模式（负离子或正离子模式，高电场或低电场）。离子阱质谱仪（ITMS）与新型IMS系统相结合，将成为研究络合离子化学的主要设备。ITMS的优点之一是可以获得离子的结构信息。通过利用和调整离子化学，将有可能改进、扩展和增强IMS的操作。与世界上最大的制造，开发和销售IMS系统的公司，英国公司史密斯检测有限公司（网址：www.smithsdetection.com和http://trace.smithsdetection.com/）的领先科学家和工程师一起，我们将进行为期四年的研究计划，以实现上述目标。通过史密斯检测有限公司，这将导致一种独特的仪器的发展，增加当前IMS系统的维度，最终导致新一代化学探测器被部署到打击犯罪和恐怖主义，并增加英国境内的安全。

The globalisation of our society means that there is an ever-increasing need, within homeland security, for reliable, real-time and sensitive detection of a wide range of substances that are a threat to our society. The chemicals to be detected range from explosives, through to illicit narcotics and chemical and biological agents. The ability to quickly and accurately measure these hazardous compounds, and distinguish them from a complex chemical environment, is vital to our nation's needs for its fight against crime and terrorism.Commonly used equipments for this type of security are often based on Ion Mobility Spectrometry (IMS), and which are often employed to screen people or objects. You may have experienced its application at airports if you had your laptop checked for traces of explosives, or if you walked through a Sentinel , used to screen people for trace amounts of explosives or narcotics. IMS is however, not only employed in transportation security, but also in military and civilian facilities.IMS operates by creating charged molecules (ions), which can either be positively or negatively charged. These ions migrate under the influence of an electric field with a mean constant velocity and collide with neutral molecules. Collisions and reactions (ion-molecule reactions) lead to the formation of other ionic species which may react with a trace gas. Changes in the resultant mobility of ions as they progress along an electric field are monitored and processed to try to identify any threat materials present.The IMS systems currently deployed have a number of limitations, including sensitivity and selectivity, which result in the technology not being fully exploited. The major limitation is low chemical specificity, restricting the type of compounds which can be readily detected. Many explosives and chemical threats just can not be detected. To overcome this requires a novel scientific approach, employing a detailed fundamental and phased research programme to understand the key chemical processes employed in IMS, and in particular to those occuring in the latest generation of drift tube systems being developed by Smiths Detection Ltd, Watford, UK. A systematic study is required which will investigate the ionization chemistry, the use of chemical dopants (to change the chemistry), and mode of operation (negative or positive ion mode, high or low electric field). An Ion Trap Mass Spectrometer (ITMS), coupled to novel IMS systems, will be the main device employed to study the complex ion chemistry. One of the advantages of the ITMS is that structural information on the ions can be obtained. By utilizing and tailoring the ion chemistry it will be possible to refine, extend, and enhance the operation of IMS. Together with lead scientists and engineers working in the world's largest company which manufactures, develops and markets IMS systems, the UK based company Smiths Detection Ltd (website address: www.smithsdetection.com and http://trace.smithsdetection.com/), we will pursue a four year programme of research to achieve the above objectives. Through Smiths Detection Ltd, this should lead to the development of a unique instrument, increasing the dimensionality of current IMS systems, ultimately leading to a new generation of chemical detectors to be deployed to fight crime and terrorism and increase security within the UK.