Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, USA.
Chemical Institute of São Carlos, University of São Paulo, São Paulo 05001, Brazil.
Lab Chip. 2024 Sep 10;24(18):4403-4421. doi: 10.1039/d4lc00223g.
Presumptive drug screening enables timely procurement of search and arrest warrants and represents a crucial first step in crime scene analysis. Screening also reduces the burden on forensic laboratories which often face insurmountable backlogs. In most scenarios, on-site presumptive drug screening relies on chemical field tests for initial identification. However, even when used appropriately, these test kits remain limited to subjective colorimetric analysis, produce false positive or negative results with excessive sample quantities, and are known to cross-react with numerous innocuous substances. Previous efforts to develop microfluidic devices that incorporate these chromogenic indicator reagents address only a few of the many challenges associated with these kits. This is especially true for samples where the drug of interest is present as a lacing agent. This work describes the development of a centrifugal microfluidic device capable of integrating facile sample preparation, by way of a 3D printed snap-on cartridge amenable to microwave assisted extraction, followed by chromatographic separation and chromogenic detection on-disc. As cannabis is among the most widely used controlled substance worldwide, and displays strong interference with these indicator reagents, mock samples of laced marijuana are used for a proof-of-concept demonstration. Post extraction, the microdevice completes high throughput metering just prior to simultaneous reaction with four of the most commonly employed microchemical tests, followed by objective image analysis in CIELAB (a device-independent color model). Separation and recovery of a representative controlled substance with 93% efficiency is achieved. Correct identification, according to hierarchical cluster analysis, of three illicit drugs (, heroin, phencyclidine, and cocaine) in artificially laced samples is also demonstrated on-disc. The cost effective microdevice is capable of complete automation post-extraction, with a total analysis time (including extraction) of <8 min. Finally, sample consumption is minimized, thereby preventing the complete destruction of forensic evidence.
初步药物筛选能够及时获得搜查和逮捕令，并代表了犯罪现场分析的关键第一步。筛选还减轻了法医实验室的负担，这些实验室通常面临着无法克服的积压。在大多数情况下，现场初步药物筛选依赖于化学现场测试进行初步鉴定。然而，即使使用得当，这些测试试剂盒仍然限于主观比色分析，对于过量的样本量会产生假阳性或假阴性结果，并且已知会与许多无害物质发生交叉反应。以前开发的微流控设备，整合了这些显色指示剂试剂，仅解决了与这些试剂盒相关的许多挑战中的一小部分。对于以加缀剂形式存在的目标药物的样本尤其如此。这项工作描述了一种离心微流控设备的开发，该设备能够通过 3D 打印的即插即用盒进行简便的样品制备，该盒子适用于微波辅助提取，然后进行色谱分离和盘上显色检测。由于大麻是全球使用最广泛的受控物质之一，并且对这些指示剂试剂显示出强烈干扰，因此使用加缀的大麻模拟样品进行概念验证演示。提取后，微设备在与四种最常用的微化学测试同时反应之前，完成高通量计量，然后进行 CIELAB（与设备无关的颜色模型）中的客观图像分析。以 93%的效率实现了对代表性受控物质的分离和回收。根据层次聚类分析，在人工加缀的样品中正确识别了三种非法药物（海洛因、苯环利定和可卡因）。成本效益高的微设备能够在提取后完全自动化，总分析时间（包括提取）<8 分钟。最后，最大限度地减少了样品消耗，从而防止了法医证据的完全破坏。
