Development of a colorimetric breath analyzer for THC

According to the 2021 World Drug Report cannabis continues to be one of the most widely used drugs worldwide. UNODC estimates that almost 4% of the global population aged 15–64 years used cannabis at least once in 2019, the equivalent of some 200 million people. Cannabis is a plant composed of more than 500 compounds. The psychoactive compounds with forensic interest include Δ9-tetrahydrocannabinol (Δ9-THC), cannabidiol (CBD), Δ8-tetrahydrocannabinol (Δ8-THC), and cannabinol (CBN). Δ9-THC is the main psychoactive component in cannabis extracts. Δ9-THC ability impairs performance and decreases the ability of drivers. The requirement for measuring impairment in drivers has initiated the need for reliable and portable roadside tools capable of measuring Δ9-THC in readily accessible biological fluids such as breath, in an easy and straightforward manner. One of the best options is the use of a breathalyzer, a tool already well-known by law enforcement agents for the detection of alcohol. The commercial devices currently sold as breath analyzers for Δ9-THC detection are sampling systems containing a barrier that retains Δ9-THC. However, it needs further quantification by an instrumental technique already established for this purpose. Our aim relies on the replacement of the barrier used in the current breathalyzer systems with one that has sorptive characteristics. Modifying this sorptive barrier with a dye selectively reactive to Δ9-THC will allow the detection in situ using colorimetric or luminescent. The outcome of this project is the fundamental chemical foundation needed for the construction of a reliable semi-quantitative breathalyzer device to be applied in Driving under the Influence of Drugs (DUID) monitoring in the U.S. NCA/NCF