Chemical profiling of cocaine using portable spectroscopic techniques: Towards timely illicit drug intelligence

Chemical profiling of illicit drugs plays a key role in linking seizures and supporting investigations related to illicit drug trafficking. Separative analytical techniques, such as gas chromatography-mass spectrometry (GC-MS), remain the standard method for chemical profiling thanks to their ability to provide detailed insights into chemical composition. However, valuable intelligence generated through this process often remains unexploited by investigators, primarily because the associated analytical and administrative procedures delay its availability. These delays can impact the early phase of investigations when rapid information is most critical. This study evaluates the feasibility of using rapid and portable spectroscopic techniques to initiate the illicit drug profiling process earlier in investigations. 277 cocaine specimens were profiled using the reference GC-MS method and classified into their respective chemical classes. These specimens were also analyzed with near-infrared (NIR) and Raman spectroscopy, and pairwise spectral comparisons using the Euclidean distance metric were performed between the populations of linked (intra-variability) and unlinked (inter-variability) samples. Results demonstrate that these techniques effectively discriminate cocaine specimens identified as either linked or unlinked by the reference method, with NIR spectroscopy showing higher discrimination. Finally, the practical implementation, added value and limitations of integrating these rapid techniques into the illicit drug profiling process are discussed.