Identification of Opioid Street Drug Mixtures with Benchtop NMR and KnowItAll

The opioid crisis continues to be a severe challenge for public health organizations worldwide. According to the World Health Organization, three out of every four drug-related deaths are caused by opioid use.¹

For forensic analysts and border control officers, the challenge is not only caused by new substances frequently entering the market, but street drugs are rarely pure. They are cut with adulterants and cutting agents leaving users uncertain of what they are consuming. Some additives are worsening withdrawal symptoms, as seen with xylazine,² while others can mask or intensify opioid effects, making rapid identification a matter of public health and safety.

From an analytical perspective, opioids like heroin and fentanyl are already complex molecules that produce crowded NMR spectra. The additional adulterants make spectral interpretation even more difficult. Mixtures may even contain more than one opioid, further increasing the challenge.³ Benchtop NMR paired with Wiley’s KnowItAll software provides a practical solution, streamlining the identification of street drug mixtures.

In our recent application note, we demonstrated how forensic labs can build a custom benchtop NMR user database of common illicit drugs and cutting agents in Wiley’s KnowItAll and use it for mixture identification. The workflow includes ProcessIt, MineIt, and SearchIt, creating a smooth semi-automated workflow from a sample measurement to mixture identification in no time (Figure 1).

Figure 1. Wiley KnowItAll environment allows for seamless transition between different tools like MineIt (left), here showing a user database containing benchtop NMR spectra of illicit drug reference substances, and SearchIt (right) which performs mixture spectrum searches offering different search methods and options.

Case Study: Heroin Mixture

Among the three case studies presented in the application note: amphetamine, cocaine, and heroin, the heroin sample showed the highest degree of complexity. The ¹H NMR spectrum of the seized sample shows strong signal overlap from multiple components as it is often encountered in heroin street samples.⁴

Using KnowItAll’s SearchIt, the first result suggested heroin and paracetamol, but some non-identified signals remained. Using a three-component mixture search and applying a different search method identified caffeine as the missing piece. The Composite Spectrum feature automatically generates a combined fit spectrum for all three compounds, superimposed in red on the experimental spectrum in blue for easy visual confirmation. The mixture was ranked the best result with a hit quality index (HQI) of 73 (Figure 2).

Figure 2. Search results in KnowItAll identify the investigated sample as a mixture of paracetamol, caffeine, and heroin. The Composite Spectrum (red) is superimposed onto the experimental spectrum (blue).

Forensic analysts working in harm reduction, law enforcement, or border control need tools that deliver rapid and reliable identification under pressure of constantly evolving drug landscape especially in the context of the opioid crisis. The combination of accessible, portable benchtop NMR with the workflow-optimized KnowItAll offers a fast, practical, and user-friendly approach to illicit drug mixture identification.

For more information, please contact us under sales@nanalysis.com or visit  https://sciencesolutions.wiley.com.

References

[1] World Health Organization: WHO updates guidelines on opioid dependence treatment and overdose prevention, https://www.who.int/news/item/09-02-2025-who-updates-guidelines-on-opioid-dependence-treatment-and-overdose-prevention (accessed 2025-08-27).

[2] National Institute on Drug Abuse: Xylazine, https://nida.nih.gov/research-topics/xylazine#xylazine-withdrawal (accessed 2025-08-27).

[3] European Union Drugs Agency: Fentanyl drug profile,

https://www..euda.europa.eu/publications/drug-profiles/fentanyl_en (accessed 2025-08-27).

[4] Cole, C. et al. CUT: A guide to adulterants, bulking agents and other contaminants found in illicit drugs. Centre for Public Health, Liverpool John Moores University, 2010.