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Chemical Foundations for a Cannabis Breathalyzer


Founded in 2019, this program was motivated by the rapid decriminalization of adult use and medical use of cannabis by state governments. This has led to extensive R&D by universities and industry to invent a cannabis breathalyzer for law enforcement to identify cannabis intoxication in a field environment. Several versions of breath collection devices are being marketed for the detection of THC (delta-9-tetrahydrocannabinol) in the breath of cannabis users. THC is not directly correlated to intoxication but may indicate recent smoking or vaping. THC and other cannabinoids are non-volatile and chemically unstable, creating an as-yet-unsolved reliability challenge that did not exist for the alcohol breathalyzer. ACMD’s scientists and engineers are using their backgrounds in vapor capture and analyses to identify and quantify biomarkers linked to recent cannabis use in the exhaled breath of cannabis users.


NIST's initial work in cannabis science was a series of measurements of the vapor pressure of two important cannabinoids: delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). To move the research forward, this project is currently funded (2019-2022) by an interagency agreement with the National Institute of Justice. The collaborative work plan has three distinct, but related, aims:


  1. To characterize the volatilome of cannabis users, including cannabinoids and other chemicals and biomarkers in the breath that have typically been ignored
  2. To measure the chemical and physical properties of these compounds, including vapor pressure and blood/breath partitioning
  3. To study competitive adsorption of breath compounds with adsorbents that are critical components of devices in development


We are partnered with colleagues at the University of Colorado Boulder (CU) to obtain breath samples before and after cannabis use and are examining these samples for THC and other potential biomarkers that may specifically indicate actual intoxication from recent use. In this program area, orthogonal breath collection techniques, devices, elution methods and analyses will be compared with standard breath surrogates and real-time breath analysis. The ultimate positive impact on the criminal justice system will be a breathalyzer device that leverages the optimal materials and collects the right target compounds to detect intoxication.

Created July 15, 2020, Updated July 16, 2020