Hemp Versus Marijuana: A Breakthrough for Forensic Laboratories

In a significant breakthrough, advancements in mass spectrometry are aiding forensic laboratories in accurately differentiating hemp from marijuana, a critical task in the evolving landscape of cannabis regulation. This development comes in the wake of the 2018 Farm Bill, which legalized hemp but left law enforcement and forensic labs facing challenges in distinguishing between the two forms of cannabis.

The Controlled Substance Act of 1970 had classified cannabis as an illegal drug, listing it as a Schedule I controlled substance. The Farm Bill of 2018 marked a turning point by legalizing hemp, provided it contains 0.3% or less total THC (tetrahydrocannabinol). The challenge arose as law enforcement had to precisely measure THC levels to differentiate hemp from marijuana.

With varying cannabis regulations across states, including decriminalization and legalization for medical and recreational use, the need for precise THC measurement became crucial. In 2022, over 10% of crime lab submissions were related to distinguishing marijuana from hemp.

Two National Institute of Justice (NIJ)-supported labs addressed this challenge using cutting-edge mass spectrometry techniques: gas chromatography-mass spectrometry (GC-MS) and direct analysis in real time-high-resolution mass spectrometry (DART-HRMS).

• GC-MS Approach

  • Dr. Walter Brent Wilson’s team at the National Institute of Standards and Technology utilized GC-MS to develop a cost-effective method.
  • They identified THC extraction methods and quantified THC levels using GC-MS in different scanning modes.
  • Single-ion monitoring mode significantly improved sensitivity compared to full-scan mode.

• DART-HRMS Approach

  • Dr. Rabi Musah’s lab from the University at Albany, State University of New York, employed DART-HRMS to quantify THC in complex materials.
  • Their rapid triage approach detected cannabis-related molecules and validated protocols for measuring cannabinoid amounts.
  • DART-HRMS showcased efficiency in detecting THC in various samples with minimal pre-treatment steps.

Impact on Forensic Laboratories

The use of these advanced mass spectrometry techniques is poised to revolutionize forensic laboratories.

• Dr. Musah anticipates that DART-HRMS could reduce backlogs, reagent costs, and streamline analysis protocols.
• Dr. Wilson’s project created standard operating procedures for THC quantification, benefiting federal, state, and local forensic laboratories.

Conclusion

This groundbreaking research, supported by NIJ, not only addresses the technical challenges faced by forensic labs but also holds the potential to enhance efficiency, reduce costs, and streamline cannabis sample analysis protocols. As cannabis regulations continue to evolve, these innovations mark a significant step forward in forensic science.

Disclaimer: The work described in this article was supported by NIJ inter-agency agreement number DJO-NIJ-20-RO-0009 and NIJ grant number 2019-DU-BX-0026, awarded to the National Institute of Standards and Technology and the University of Albany, State University of New York, respectively.

Full report can be accessed here.