Approximately 20 years ago, instrumental methods made their way out of the laboratory and into the field and were quickly applied in chemical threat defense. Over the years these instruments were hardened, operated with battery power, made smaller and lighter, and became a good fit within chemical threat response operations. These portable and hand-held instruments, which include sophisticated analytical chemistry tools such as optical spectroscopy, mass spectrometry, and chromatography, are also valuable methods for the chemical analysis of narcotics and street drugs. The opioid epidemic and the increase in the number of new psychoactive substances (NPS) has taxed the system dealing with the drug crisis. Timely but accurate identification of narcotics is important for evidence collection and probable cause determinations where the backlog in forensic laboratories can be a hinderance. Also, responders may encounter a toxic, contaminated environment where chemical analysis information is necessary to determine the required personal protective ensemble (PPE) and necessary site mitigation.
Street drug compositions can present challenges for in-field analyses. As the toxicity of fentanyl derivatives is especially high, the concentration of the fentanyl compound in the street drug should be relatively low, 1% or less by weight. The bulk of the fentanyl-containing street drug powder or tablet is composed of benign cutting agents and may also include other narcotics. For optical spectroscopy methods used in the field, it is generally not feasible to identify components at low fractional concentrations due to interference from the higher concentration components.
This presentation will concern the design and testing of a disposable, concentration-extraction kit used in conjunction with instrumental methods for in-field analysis of street drug mixtures, targeted towards fentanyl derivatives. The kit relies on the fact that fentanyl and other narcotics appear as hydrochloride (HCl) salts in street drugs. The HCl salt is converted to the base form and concentrated into an organic solvent, increasing the available concentration of the opioid and removing interference from most cutting agents. A portion of the organic phase is presented to the instrumental method. A hand-held Fourier transform infrared (FT-IR) spectrometer was used to test the identification performance of isolates from narcotic surrogate samples and laboratory produced narcotic drug mixtures. The hand-held FT-IR incorporates a diamond attenuated total reflection (ATR) sample interface. Microliter quantities of the organic phase are delivered from the kit dispenser to the diamond interface and the dispensed solvent is allowed to evaporate. The IR spectrum of isolated material in contact with the diamond is recorded and analyzed using specialized IR spectral search methods. The testing results indicate that 1% by weight fentanyl can be identified in mixture compositions that approximate counterfeit oxycodone tablets. More complicated mixtures resulted in coextractions of the target compound and other components such as xylazine, noscapine, quinine, and heroin. Finally, results will be presented for the use of the kit in the IR spectroscopic analysis of acquired street drugs – a fentanyl containing counterfeit oxycodone tablet and a cannabinoid impregnated paper.