Supplementary information files for differentiation of body fluid stains using a portable, low-cost Ion Mobility Spectrometry device – A pilot study

Supplementary files for article Differentiation of body fluid stains using a portable, low-cost ion mobility spectrometry device—a pilot studyThe identification and recovery of suspected human biofluid evidence can present a bottleneck in the crime scene investigation workflow. Crime Scene Investigators typically deploy one of a number of presumptive enhancement reagents, depending on what they perceive an analyte to be; the selection of this reagent is largely based on the context of suspected evidence and their professional experience. Positively identified samples are then recovered to a forensic laboratory where confirmatory testing is carried out by large lab-based instruments, such as through mass-spectrometry-based techniques. This work proposes a proof-of-concept study into the use of a small, robust and portable ion mobility spectrometry device that can analyse samples in situ, detecting, identifying and discriminating commonly encountered body fluids from interferences. This analysis exploits the detection and identification of characteristic volatile organic compounds generated by gentle heating, at ambient temperature and pressure, and categorises samples using machine learning, providing investigators with instant identification. The device is shown to be capable of producing characteristic mobility spectra using a dual micro disc pump configuration which separates blood and urine from three visually similar interferences using an unsupervised PCA model with no misclassified samples. The device has the potential to reduce the need for potentially contaminating and destructive presumptive tests, and address the bottleneck created by the time-consuming and laborious detection, recovery and analysis workflow currently employed.This dataset describes the analysis of dried biofluid spots using a portable ion mobility mass spectrometer fitted with a thermal desorption probe. It includes blood, urine and visually similar contaminants.<br>

《使用便携式低成本离子迁移谱（ion mobility spectrometry）设备区分体液斑痕——一项初步研究》论文补充材料

人体体液类疑似物证的识别与提取，往往是犯罪现场勘查流程中的瓶颈环节。犯罪现场勘查人员通常会根据其对分析物的初步判断，选用多款推定增强试剂；这类试剂的选择主要基于疑似物证的情境与勘查人员的专业经验。经初步确证为阳性的样本将被移送至法医实验室，由大型实验室仪器（如基于质谱技术的检测方法）完成确证检测。

本研究开展了一项概念验证研究，探讨使用小型、坚固且便携的离子迁移谱设备开展现场原位分析的可行性：该设备可在现场对样本进行分析，检测、识别并区分常见体液与干扰物。该分析通过在环境温压条件下温和加热产生的特征挥发性有机化合物实现检测与识别，并借助机器学习对样本进行分类，为勘查人员提供即时的识别结果。

实验结果显示，该设备采用双微型圆盘泵配置可生成特征迁移谱，通过无分类错误的无监督主成分分析（Principal Component Analysis, PCA）模型，可将血液与尿液从三种视觉相似的干扰物中有效区分。

该设备有望减少潜在具有污染性与破坏性的推定检测需求，并解决当前采用的耗时耗力的检测、提取与分析流程所造成的瓶颈问题。

本数据集记录了使用搭载热脱附探针的便携式离子迁移谱质谱仪对干燥体液斑痕开展的分析，涵盖血液、尿液及视觉相似的干扰物样本。