便携式拉曼光谱仪用于合成大麻素类物质快速定性分析探究

我国于2021年7月将合成大麻素类物质整类列入管制，在一线查缉现场对疑似合成大麻素样品进行快速定性分析是办案民警的迫切需求。研究系统考察了拉曼光谱对合成大麻素的整体区分能力，比较了四款手持式拉曼光谱仪分析实际缴获样品时的结果差异，探讨了制约拉曼光谱在一线查缉现场广泛应用的原因。ProTT-EZRaman-A7便携式拉曼光谱仪的整体性能介于台式拉曼和手持式拉曼之间，选用该仪器采集了90种合成大麻素对照品的拉曼光谱，并利用兼容性强的KnowItAll软件建立了90种合成大麻素通用拉曼光谱库。分析90种合成大麻素的拉曼光谱，结果表明，当不存在荧光干扰时，拉曼光谱可以区分所有合成大麻素物质，但对部分结构相差一个甲基、卤素原子等的结构类似物区分度欠佳。不同款拉曼光谱仪的性能差异大，为考察其原因，本研究选用了四款手持式拉曼光谱仪分别对120份实际缴获合成大麻素样品进行了测定，随后使用KnowItAll软件并选用包含90种合成大麻素的通用拉曼光谱库对每张光谱图进行谱库检索。四款手持式拉曼光谱仪的正确匹配率分别为71.7%, 68.3%, 46.7%和24.2%。抗荧光干扰能力和分辨率的不同是造成不同...

Rapid Qualitative Analysis of Synthetic Cannabinoids by Raman Spectroscopy

In July 2021, China imposed a class-wide ban on synthetic cannabinoids, with the definition of synthetic cannabinoids by seven core structures. It is an urgent need for the drug law-enforcing departments and relevant technicians to conduct in-field rapid qualitative analysis of suspected synthetic cannabinoid samples. This study investigated the overall discriminant ability of Raman spectroscopy for synthetic cannabinoids, compared four handheld Raman spectrometers, and discussed the possible reasons that restricted the wideapplication of Raman spectroscopy. ProTT-EZRaman-A7 portable Raman spectrometer, with the overall performance between desktop Raman and handheld Raman, was selected to collect the Raman spectra of 90 synthetic cannabinoid reference substances. Then a general Raman spectrum library with 90 synthetic cannabinoids was established using KnowItAll software, which was compatible with various original spectrum formats. The analysis of 90 synthetic cannabinoid Raman spectra found that when there was no fluorescence interference, Raman spectroscopy could distinguish all synthetic cannabinoids, but showed a low discriminant ability for some structural analogues, especially those with a difference of a methyl or a halogen atom. The performance of different Raman spectrometers varied greatly, so in order to investigate the reasons for that performance differences, four handheld Raman spectrometers were selected to analyze 120 seized synthetic cannabinoid samples. Then the library search was performed using the KnowItAll software and the established general Raman spectrum library. The correct matching rates of the four Raman spectrometers were 71.7%, 68.3%, 46.7%, and 24.2%, respectively. The difference in background fluorescence reduction effect and resolution attributed to that result. The portable Raman spectrometer was simple, fast, and can be used for in-field testing. However, Raman spectroscopy can only be used for preliminary qualitative screening considering the unknown purity of the seized samples, the possible fluorescence interference, the performance of different Raman spectrometers, and the spectral library completeness. This study provided guidance for forensic science laboratories and relevant technicians to apply the Raman spectrum results correctly.