Identification of Drug-related Compounds in Body Fluid Stains on Forensically Relevant Surfaces at Atmospheric Pressure using DESI Mass Spectrometry

使用 DESI 质谱法在大气压下鉴定法医学相关表面上体液污渍中的药物相关化合物

• 批准号: EP/D036240/1
• 负责人: Martin McCoustra
• 金额: $ 8.05万
• 依托单位: University of Nottingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FD036240%2F1
• 关键词: Identification; Drug; related; Compounds; Body

Forensic investigations frequently involve the analysis of body fluids spilled during the commissioning of a crime, leading to deposits on a wide range of surfaces such as carpets, walls, clothing, bedlinen and skin. Testing of, for example, bloodstains for the presence of drugs and drug-related metabolites or other biomarkers can be a highly complex procedure, and the success rate of such analyses can be severely limited due to loss of material during extraction, as well as a lack of absolute sensitivity. Moreover, the inherently destructive nature of these tests - specimens need to be removed from the bulk item before any extraction can be carried out - is a major issue, as is the fact that analysis is invariably carried out at a laboratory remote from the scene. The necessity for remote analysis does also add potentially crucial time to the investigative process, as well as carrying an inherent risk of sample degradation and contamination in transit and subsequent storage. Perhaps most importantly: if it is not feasible to remove a suitable sample from an item, potentially useful information will not be available to investigating officers. Therefore, forensic practitioners have considerable interest in technologies which could potentially overcome at least some of these important limitations.In this proposal we intend to undertake a feasibility study to assess a novel application of the established technique of mass spectrometry in such forensic investigations. Mass spectrometry is a very powerful and well-established technique able to detect minute amounts of materials with very high sensitivity and specificity. Unfortunately, it has some serious drawbacks which severely restrict its applicability. These drawbacks chiefly concern the sampling of the materials under investigation, which have to be capable of being in the gas phase. This tends to be especially difficult from solid substrates, necessitating physical removal and dissolution of the material of interest, bombardment of the sample with highly energetic ions in an ultrahigh vacuum chamber, or illumination of the sample with an intense laser beam after application of a matrix material. All these methods are highly problematic in the field of forensic analysis, where integrity of the subject is of utmost importance. A methodology to volatilise materials of interest for mass spectrometric analysis which is compatible with forensic requirements would thus have great potential.The newly-introduced technique of DESI, short for desorption electrospray ionisation, has such potential, as yet to be realised, to become a fully-fledged routine surface analytical tool, marrying the analytical capabilities of mass spectrometry with a sampling facility convenient for forensic analyses. As opposed to most other such techniques, it is applicable under a wide range of environmental conditions and suitable for a wide array of samples including surfaces of biological, pharmaceutical, polymer, metal and mineral materials. Moreover, current technical capabilities are such that a great deal of miniaturisation is possible, leading to a desktop-sized or potentially even a portable device.The proposed work focuses on the application of the technique to forensically relevant subjects and materials, more specifically the detection of drugs and drug metabolites in body fluid stains found at scenes of crime. Direct comparisons will be made with mass spectra generated using two established mass spectrometry techniques capable of surface analysis available in the School of Pharmacy, secondary ion mass spectrometry (SIMS) and matrix assisted laser desorption-ionisation (MALDI), which both employ different methods of volatilisation. It should be stressed that whereas this proposal concentrates on a very specific sample type, the technique has the clear potential for application to a much wider range of samples in the forensic science field.

法医调查经常涉及对犯罪过程中溢出的体液进行分析，导致在地毯、墙壁、衣服、床上用品和皮肤等各种表面上都有沉积物。例如，对血迹进行药物和药物相关代谢物或其他生物标记物的检测可能是一个高度复杂的过程，并且由于提取过程中材料的损失以及缺乏绝对灵敏度，这种分析的成功率可能受到严重限制。此外，这些测试固有的破坏性——在进行任何提取之前需要从散装物品中取出样本——是一个主要问题，因为分析总是在远离现场的实验室进行。远程分析的必要性也为调查过程增加了潜在的关键时间，并且在运输和随后的储存过程中存在样品降解和污染的固有风险。也许最重要的是：如果无法从物品中提取合适的样本，调查人员将无法获得可能有用的信息。因此，法医从业人员对可能克服这些重要限制中的至少一些的技术有相当大的兴趣。在本提案中，我们打算进行可行性研究，以评估已建立的质谱技术在此类法医调查中的新应用。质谱法是一种非常强大和成熟的技术，能够以非常高的灵敏度和特异性检测微量物质。不幸的是，它有一些严重的缺点，严重限制了它的适用性。这些缺点主要涉及所调查材料的取样，它必须能够处于气相。对于固体基材，这往往是特别困难的，需要物理去除和溶解感兴趣的材料，在超高真空室中用高能离子轰击样品，或在应用基体材料后用强激光束照射样品。所有这些方法在法医分析领域都是非常有问题的，在法医分析领域，主体的完整性是最重要的。因此，一种符合法医要求的挥发质谱分析感兴趣的材料的方法将具有巨大的潜力。新引入的DESI技术（解吸电喷雾电离的简称）具有这样的潜力，但尚未实现，它将成为一种成熟的常规表面分析工具，将质谱分析能力与方便法医分析的采样设施结合起来。与大多数其他此类技术相反，它适用于广泛的环境条件，适用于各种样品，包括生物，制药，聚合物，金属和矿物材料的表面。此外，目前的技术能力使得大量的小型化成为可能，从而导致台式机大小甚至可能是便携式设备。拟议的工作重点是将该技术应用于与法医有关的主题和材料，更具体地说，是在犯罪现场发现的体液污渍中检测药物和药物代谢物。将直接比较使用两种已建立的质谱技术产生的质谱，这些技术能够在药学院进行表面分析，即二次离子质谱（SIMS）和基质辅助激光解吸-电离（MALDI），这两种技术都采用不同的挥发方法。应该强调的是，虽然这项建议集中于一种非常具体的样品类型，但该技术显然有潜力应用于法医科学领域更广泛的样品。