Evaluation of spectroscopic techniques for on‐site drug testing of festival seizures

Abstract

AbstractDespite the fact that drugs of abuse are illegal, a drug‐free festival still remains an utopia in most settings. For law enforcement purposes, it is necessary to rapidly determine whether controlled substances are involved. On‐site testing is a challenging task because drugs appear in different physical forms and concentrations. The aim of this study was to compare the performance of two spectroscopic techniques, Raman and Fourier transform‐infrared (FT‐IR), for the testing of drug seizures at a dance festival. First, samples were measured through packaging with Raman. Subsequently, homogenized samples were analysed with FT‐IR. For MDMA tablets, a chemometric model was applied on the FT‐IR spectra for the dose estimation. After the festival, results were confirmed in the forensic laboratory with gas chromatography coupled with mass spectrometry (GC–MS) and gas chromatography with flame ionization detection (GC‐FID). In total, 166 samples of which 90 tablets, 53 powders, 16 crystals and 7 liquids were analysed. MDMA, cocaine and ketamine were the top three drugs seized. The Raman technique was suitable for powders and crystals (sensitivity of 100% and 81%, respectively). However, in comparison with FT‐IR, Raman performance was lower for the analysis of liquids (sensitivity of 67%) and ‘ecstasy’‐like tablets (sensitivity of 41%). Overall, sensitivities above 95% were obtained with FT‐IR. The MDMA doses of the tablets, determined on‐site, ranged between 52 mg and 336 mg MDMA hydrochloride. For a quick identification of a variety of drugs on‐site, the combination of Raman and FT‐IR is recommended. It should be emphasized that optimized settings, in‐house libraries and analysis by trained operators are essential to obtain correct results.