Analysis of Synthetic Cannabinoids from Urine for Forensic Toxicology using Oasis HLB μElution plates and CORT ECS UPLC Columns

Significance of the Topic

Synthetic cannabinoids marketed as legal cannabis alternatives have proliferated in recent years, presenting major challenges for forensic toxicology laboratories tasked with drug screening and law enforcement support. These designer compounds often evade regulation through minor structural modifications, and their potent psychoactive effects and metabolic complexity necessitate robust analytical methods for reliable detection in biological matrices such as urine.

Objectives and Study Overview

This study aims to develop and validate a rapid, universal extraction and analysis workflow for a panel of 22 synthetic cannabinoids and their metabolites in human urine. The approach focuses on achieving efficient recovery, baseline separation of structural isomers, and high-throughput performance using modern solid-phase extraction and UPLC-MS/MS instrumentation.

Methodology

Key steps in the sample preparation and analysis included:

• Enzymatic hydrolysis of urine samples with β-glucuronidase at pH 7.0 to release conjugated metabolites.
• SPE using Waters Oasis HLB µElution plates for simultaneous extraction of acidic, neutral, and basic analytes.
• Chromatographic separation on a Waters CORTECS UPLC C18 column (1.6 µm, 2.1×100 mm) under gradient elution with formic acid–water and acetonitrile mobile phases.
• Quantitative detection by ESI positive-mode tandem MS (MRM) using a Waters Xevo TQD instrument.

Used Instrumentation

• Oasis HLB µElution 96-well plates
• CORTECS UPLC C18 column (2.1×100 mm, 1.6 µm)
• ACQUITY UPLC I-Class system
• Xevo TQD mass spectrometer

Main Results and Discussion

All 22 analytes were resolved within 7.5 minutes with peak widths under 3 seconds. The CORTECS column provided baseline separation of critical isobaric pairs that co-eluted on fully porous columns, improving resolution by up to 23 %. Extraction recoveries averaged 74 % (range 44–102 %) with matrix effects from –49 % to +32 %, demonstrating sufficient sensitivity. Calibration curves were linear (R² > 0.985) over 0.5–100 ng/mL, with LODs as low as 0.1 ng/mL. Quality control samples showed accuracy within 90–111 % and precision below 15 % RSD across low, medium, and high concentration levels.

Benefits and Practical Applications

This method offers a rapid, reliable workflow for forensic laboratories, enabling universal extraction of diverse cannabinoid structures without evaporation steps and ensuring high-throughput analysis with improved chromatographic performance. It supports accurate monitoring of synthetic cannabinoid use and assists law enforcement in controlling emerging designer drugs.

Future Trends and Potential Applications

As new synthetic cannabinoids continue to appear, the demonstrated extraction and UPLC-MS/MS platform can be readily adapted to novel analogs with minimal method adjustments. Future work may extend to other biological matrices, miniaturized SPE formats, and high-resolution mass spectrometry for broader screening capabilities.

Conclusion

A robust analytical procedure combining Oasis HLB µElution SPE and CORTECS UPLC separation with Xevo TQD detection has been developed for comprehensive screening of synthetic cannabinoids and metabolites in urine. The method delivers fast analysis, excellent resolution, and reliable quantitation suitable for forensic toxicology applications.

References

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• 4. Sobolevsky T et al. Forensic Sci Int (2010) 200(1):141-147