Determination of Heroin in Street Drug Samples

Significance of the Topic

Rapid, reliable field detection of heroin and other opioids is critical for law enforcement and forensic laboratories. Minimally invasive sampling techniques with minimal sample preparation reduce analysis time and exposure to hazardous materials. Printable Surface Enhanced Raman Scattering (P-SERS) combined with handheld Raman devices offers a promising approach to detect trace narcotics in street samples.

Study Objectives and Overview

This study evaluated Metrohm’s new ID Kit for opioid detection using the Mira DS handheld Raman analyzer equipped with P-SERS substrates. The aims were to confirm heroin presence in 18 crude street samples and to identify the optimal solvent for sample extraction with respect to extraction efficiency, spectral clarity, and safety considerations.

Methodology

• Samples: Eighteen light brown powder or crystalline heroin samples (1–5 mg) confirmed by GC/MS.
• Solvent Screening: Tested water, ethanol, methanol, dichloromethane, chloroform, acetonitrile, ethyl acetate, and acetic acid.
• Extraction Protocol: 1–2 mg of sample mixed with 250 µL solvent, shaken, solids settled, and 10 µL supernatant applied to P-SERS substrate.
• Spectral Acquisition: Laser power set to 1–2 for solvent study and 2–3 for detection; integration times of 0.5–1 s; two averages; raster off.

Instrumentation Used

• ID Kit P-SERS (cat. 607506400)
• Mira DS Raman Analyzer (cat. 2.926.0020)
• MiraCal DS Software (cat. 606071010)
• SERS Smart Attachment (cat. 607506040)

Results and Discussion

• All tested solvents enabled detection of heroin signature peaks at 531, 625, and 1336 cm–1, but ethyl acetate provided the cleanest spectra with minimal fluorescence and background interference.
• P-SERS substrates effectively quenched fluorescence observed in classic Raman analysis of crude street heroin, revealing clear heroin peaks even in high-fluorescence samples.
• Heroin was positively identified in all 18 street samples. Automated detection algorithms on the Mira DS yielded immediate positive opioid identification on the hazard screen.

Benefits and Practical Applications

• Rapid on-site detection with minimal sample preparation reduces analysis time to under a minute per sample.
• Printable SERS substrates are user-friendly and compatible with handheld instruments, supporting field and laboratory workflows.
• Automated spectral matching and decision-making algorithms streamline data interpretation and reporting.

Future Trends and Potential Uses

• Expansion of ID Kit libraries to cover a broader range of illicit substances and cutting agents.
• Integration with advanced data analytics and cloud-based databases for real-time monitoring and intelligence sharing.
• Development of solvent-free or minimal-solvent extraction techniques to further simplify field protocols.
• Miniaturization of SERS substrates and multiplexed detection strategies for simultaneous screening of multiple drugs.

Conclusion

Metrohm’s ID Kit with P-SERS and Mira DS handheld Raman analyzer demonstrates reliable, rapid heroin detection in street samples. Ethyl acetate extraction offers optimal spectral clarity. The approach enhances field and forensic analyses by combining simplicity, speed, and automated interpretation.

References

• Metrohm White Paper WP-034EN, January 2021