Elkins Kelly M, Weghorst Alex C, Quinn Alicia A, Acharya Subrata
Chemistry Department, Towson University, 8000 York Road, Towson, MD, 21252, USA.
Computer and Information Sciences Department, Towson University, 8000 York Road, Towson, MD, 21252, USA.
Drug Test Anal. 2017 Feb;9(2):306-310. doi: 10.1002/dta.1949. Epub 2016 Feb 9.
Crime scene investigators (CSIs) often encounter unknown powders, capsules, tablets, and liquids at crime scenes, many of which are controlled substances. Because most drugs are white powders, however, visual determination of the chemical identity is difficult. Colourimetric tests are a well-established method of presumptive drug identification. Positive tests are often reported differently, however, because two analysts may perceive colour or record colourimetric results in different ways. In addition to perceiving colour differently, it is very common for there to be poor visibility conditions (e.g. rain, darkness) while performing these tests, further obscuring the results. In order to address these concerns and to create uniformity in the reporting of on-site colourimetric test results, this study has evaluated two of the state-of-the-art apps (ColorAssist® and Colorimeter®) for reporting the colour test results quantitatively in red-green-blue (RGB) format. The compiled library database of presumptive test results contains over 3300 data points including over 800 unique drug/test combinations. Variations observed between test replicates, from performing a test on different days, recording with a different device type (e.g. iPod Touch, iPhone models 4, 5c, 5s, or 6), and using different quantities of drug are discussed. Overall, the least variation in Euclidian norm was observed using ColorAssist® with the camera light (25.1±22.1) while the variation between replicates and data recorded using different devices was similar. The resulting library is uploaded to a smartphone application aimed to aid in identifying and interpreting suspected controlled substance evidence. Copyright © 2016 John Wiley & Sons, Ltd.
犯罪现场调查人员（CSI）在犯罪现场经常会遇到不明粉末、胶囊、片剂和液体，其中许多是受控物质。然而，由于大多数毒品都是白色粉末，因此很难通过视觉确定其化学身份。比色测试是一种公认的推定毒品鉴定方法。然而，阳性测试结果的报告方式往往不同，因为两名分析人员可能以不同的方式感知颜色或记录比色结果。除了对颜色的感知不同外，在进行这些测试时，能见度条件不佳（如下雨、黑暗）的情况也很常见，这进一步模糊了测试结果。为了解决这些问题并使现场比色测试结果的报告保持一致，本研究评估了两款最先进的应用程序（ColorAssist®和Colorimeter®），以红绿蓝（RGB）格式定量报告颜色测试结果。推定测试结果的汇编库数据库包含超过3300个数据点，包括800多个独特的药物/测试组合。讨论了在不同日期进行测试、使用不同设备类型（如iPod Touch、iPhone 4、5c、5s或6型号）记录以及使用不同数量药物时，测试重复之间观察到的差异。总体而言，使用ColorAssist®和相机灯光时，欧几里得范数的变化最小（25.1±22.1），而不同设备记录的重复数据之间的差异相似。最终的数据库已上传到一个智能手机应用程序中，旨在帮助识别和解释疑似受控物质证据。版权所有©2016约翰·威利父子有限公司。
