Detecting New Designer Cannabinoids in Herbal Incense using LC-MS-MS with Fast Precursor Ion Scanning

Significance of the Topic

Designer cannabinoids continue to emerge as synthetic alternatives to natural cannabis compounds, challenging forensic and clinical laboratories to detect substances not covered by existing screening methods. Rapid and comprehensive analytical techniques are essential to monitor public health risks, support law enforcement and regulatory compliance, and guide treatment of intoxications.

Objectives and Study Overview

This study aimed to develop a liquid chromatography–tandem mass spectrometry method employing fast precursor ion scanning to detect known and novel napthoyl-indole designer cannabinoids in herbal incense products and their metabolites in human urine. The approach sought to maximize sensitivity and broaden the scope of screening beyond conventional MRM-based workflows.

Methodology

Electrospray ionization with continuous polarity switching was combined with an ultra‐high‐performance liquid chromatograph and a fast‐scanning triple quadrupole mass spectrometer (LCMS‐8040). Key steps included:

• Use of a Restek 3 µm Ultra Biphenyl column for enhanced separation of isomeric cannabinoids and metabolites.
• Mobile phases of 0.1 % formic acid in water (Pump A) and 0.1 % formic acid in acetonitrile (Pump B) at 0.5 mL/min.
• Precursor ion scans targeting common fragment ions (m/z 127, 144, 155) at 5 000 u/sec.
• Data‐dependent MS/MS acquisition and full‐scan MS when needed to capture unexpected analogues.

Instrumentation Used

• Shimadzu LCMS‐8040 triple quadrupole mass spectrometer with UF Lens and UF Sweeper-II collision cell.
• Shimadzu Nexera ultra‐high‐performance liquid chromatograph.
• Restek Ultra Biphenyl UHPLC column (2.1 × 50 mm, 3 µm particles).

Main Results and Discussion

Fast precursor ion scans revealed characteristic peaks corresponding to napthoyl-indole cannabinoids in an herbal incense extract. A peak at 7.5 min with precursor m/z 342 was identified as JWH-018 by matching retention time and MS/MS spectrum against a spectral library. Common product ions at m/z 127, 144 and 155 provided broad coverage of the napthoyl-indole class, enabling detection of structurally modified analogues. Analysis of urine from an exposed subject confirmed JWH-018 and its metabolites, such as JWH-018-4-hydroxyindole, using high-sensitivity DDA MS/MS at 15 000 u/sec.

Benefits and Practical Applications

This method offers:

• Rapid screening of herbal products for existing and emerging designer cannabinoids without a priori knowledge of every analogue.
• High sensitivity for trace-level detection in biological matrices.
• Flexibility to incorporate new fragment ions or neutral loss scans as chemotypes evolve.

Future Trends and Possibilities

Extending this fast precursor ion approach could enable comprehensive screening of other designer drug classes such as synthetic opioids, stimulants and barbiturates. Integration with high-resolution mass spectrometry, automated spectral library expansion, and machine-learning-based data mining may further accelerate the identification of novel psychoactive substances.

Conclusion

Fast precursor ion scanning combined with data‐dependent MS/MS on the LCMS‐8040 provides a robust platform for the detection of known and yet-to-be-discovered designer cannabinoids in both herbal incense products and biological samples. This workflow enhances laboratory readiness to respond to the continually evolving landscape of synthetic cannabinoids.