Comparing GC–MS with Field-Deployable Spectroscopy for Timely Drug Intelligence

While separative analytical techniques, such as gas chromatography-mass spectrometry (GC-MS), remain the standard method for chemical profiling of illicit drugs due to their ability to provide detailed insights into chemical composition, useful data produced through this technique is frequently unable to be used by investigators because the analytical and administrative procedures associated with them delay their availability. Researchers at the University of Lausanne (Switzerland) evaluated the benefits of using quick, portable spectroscopic equipment and techniques for initiating the illicit drug profiling process earlier in investigations. Cocaine specimen samples were profiled using the reference GC-MS method, classified into their respective chemical classes, and also analyzed with near-infrared (NIR) and Raman spectroscopy. A paper based on this work was published in Forensic Science International (1).

Combating drug trafficking continues to be an enduring and difficult worldwidechallenge, requiring adaptive and innovative strategies to disrupt criminal networks (2). Among the more widely implemented and promoted techniques is illicit drug profiling, which involves chemical or physical characterization of seized samples (3). The research team noticed that, despite extensive laboratory resources invested in profiling and numerous chemical links identified, only a small proportion of the transmitted information was actually used by law enforcement in their investigations. This was mainly due to delays in transmitting profiling results, which were largely caused by time-consuming analytical and administrative processes in the laboratory. These delays often meant that the information arrived too late to be of practical use to investigators. (4,5).

These laboratories are mainly relying on separative analytical techniques to perform profiling, such as gas chromatography-mass spectrometry (GC-MS), considered to be the gold standard for chemical profiling of illicit drugs (6). However, the delays associated with the technique result in substantial obstacles; the information resulting from analysis is most valuable to the investigators as early as possible in the process for confirming or supporting their hypotheses and guiding their actions and decision-making (7). Many forensic science disciplines have taken to carrying out analyses directly in the field to overcome the constraints related to time and laboratory workload that result in these delays (8). Although previous papers have considered (4) and championed (9) the potential of these NIR and Raman spectroscopic methods in a remote profiling perspective, feasibility studies and practical applications remain limited, thus inspiring the current study (1).

The University of Lausanne research team profiled 277 cocaine specimens using the reference GC-MS method and classified them into their respective chemical classes. These specimens were also analyzed with 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. The team reported that portable spectroscopic techniques can discriminate between linked and unlinked cocaine samples, with NIR spectroscopy performing better than Raman spectroscopy. NIR spectroscopy yielded higher false positive and false negative rates than traditional GC-MS profiling, but they state that this is to be expected, as the technique does not provide the same depth of information as GC-MS profiling (1).

“These findings indicate that rapid analytical techniques, particularly NIR spectroscopy, can provide preliminary assessments of chemical similarity earlier in investigation and support timely decision-making,” the authors noted. They stated that future studies will concentrate on the operational deployment of NIR technology for chemical profiling in collaboration with police partners and should also focus on the comparison of results within and between instruments to demonstrate the practical application of the technique for large-scaled profiling (1).

Read More on Similar Topics:

Spectroscopy Outside the Laboratory

References

1. Charest, M.; Meola, S.; Gasté, L. et al. Chemical Profiling of Cocaine Using Portable Spectroscopic Techniques: Towards Timely Illicit Drug Intelligence. Forensic Sci. Int. 2025, 379, 112753. DOI: 10.1016/j.forsciint.2025.112753
2. World Drug Report 2024. United Nations Office on Drugs and Crime website.2024. https://www.unodc.org/unodc/data-and-analysis/world-drug-report-2024.html
3. Esseiva, P.; SIoset, S.; Anglada, F. et al. Forensic Drug Intelligence: An Important Tool in Law Enforcement. Forensic Sci. Int. 2007, 167 (2-3), 247-254, DOI: 10.1016/j.forsciint.2006.06.032
4. Meola, S.; Esseiva, P. What is the Future of Illicit Drug Profiling in Switzerland? Condemned to Disappear or Forgotten Treasure. Drug Test. Anal.2022, 14 (3), 411-415. DOI: 10.1002/dta.3167
5. Meola, S.; Huhtala, S.; Broseus, J. et al. Illicit Drug Profiling Practices in Finland: An Exploratory Study About End Users' Perceptions. Forensic Sci. Int. 2021, 324, 110848. DOI: 10.1016/j.forsciint.2021.110848
6. Collins, M. Illicit Drug Profiling: A Historical Perspective. Drug Test. Anal. 2022, 14 (3), 404-410. DOI: 10.1002/dta.3144
7. Morelato, M.; Beavis, A.; Tahtouh, M. et al. The Use of Forensic Case Data in Intelligence-Led Policing: The Example of Drug Profiling. Forensic Sci. Int. 2013, 226 (1-3), 1-9. DOI: 10.1016/j.forsciint.2013.01.003
8. Casey, E.; Ribaux, O.; Roux, C. The Kodak Syndrome: Risks and Opportunities Created by Decentralization of Forensic Capabilities. J. Forensic Sci. 2019, 64 (1), 127-136. DOI: 10.1111/1556-4029.13849
9. Coppey, F.; Becue, A.; Sacre, P. Y. et al. Providing Illicit Drugs Results in Five Seconds Using Ultra-Portable NIR Technology: An Opportunity for Forensic Laboratories to Cope with the Trend Toward the Decentralization of Forensic Capabilities. Forensic Sci. Int. 2020, 317, 110498. DOI: 10.1016/j.forsciint.2020.110498