Fentanyl in the Mail

Importance of Topic

Illicit drugs entering correctional facilities pose serious health and security risks. Fentanyl, in particular, is highly potent and can be absorbed through minimal contact, endangering staff and inmates alike. A rapid, accurate, and noninvasive detection method for drug residues on mail is critical to reduce overdose incidents and improve safety in prison environments.

Objectives and Study Overview

This application note evaluates Metrohm Raman’s portable systems for on-site trace detection of fentanyl on paper. The study demonstrates the sensitivity limits, outlines a practical sampling workflow, and presents real-world performance data using Surface-Enhanced Raman Spectroscopy (SERS).

Instrumentation

Two Metrohm Raman analyzers were employed:

• MISA Advanced: A handheld SERS system featuring Orbital‐Raster‐Scan technology, integrated nanoparticle solutions, P-SERS strips, and Bluetooth/USB connectivity.
• MIRA XTR DS: A benchtop/portable Raman unit with dual Raman/SERS capability, 785 nm laser, advanced fluorescence rejection algorithms, and optional attachments for universal, vial, right-angle, and SERS sampling.

An ID Kit with silver colloid nanoparticles facilitated SERS experiments.

Methodology

Notebook paper was cut into 0.635 cm² squares and spiked with fentanyl solutions from 0.1 µg to 5 µg per square. After drying, each square was placed in a vial containing silver colloid, shaken, rested, and mixed with saline. Samples were analyzed using the ID Kit OP protocol on both MIRA XTR DS and MISA systems. Spectral data were matched against illicit-materials libraries for positive identification.

Main Results and Discussion

Direct Raman analysis only revealed the paper substrate, failing to detect trace fentanyl. SERS, however, produced strong characteristic peaks even at 0.5 µg per 0.635 cm², well below lethal human doses. The four-step workflow provided clear, reproducible identifications within minutes, demonstrating high sensitivity and specificity for fentanyl in a complex paper matrix.

Benefits and Practical Applications

• Rapid on-site screening without sample destruction.
• Minimal training required for corrections personnel.
• Reduced risk of accidental fentanyl exposure.
• Cost and time savings compared to full mail digitization.

Future Trends and Potential Uses

The integration of larger spectral libraries and AI-driven algorithms will enhance identification of emerging analogues. Miniaturized SERS substrates and automated sample handling could streamline workflows. Expanding this approach to other contraband matrices (textiles, personal items) will further bolster security measures.

Conclusion

Metrohm Raman’s dual Raman/SERS platforms offer an effective solution for detecting fentanyl-laced mail in correctional settings. Their portability, high sensitivity, and ease of use help safeguard personnel and inmates while streamlining operational processes.

References

1. Metrohm AG. Application Note AN-RS-035: Fentanyl in the Mail – Strategic Detection of Illicit Drugs in Prison Mail.