Detection of Gas-Phase Cannabinoids

Abstract

Recent changes in the legal status of cannabis augmented by a rapidly evolving social acceptance towards its consumption, highlight the immediate need for a reliable, non-invasive, point-of-use detection method for cannabis intoxication. Marijuana intoxication reduces motor coordination, slows reaction time, and impairs peripheral vision, concentration, and decision making. The rise in access and consumption of marijuana is anticipated to lead to an increase in drivers and workers impaired from its effects. Current tests for marijuana consumption are invasive (rely on blood/urine), logistically challenging (require weeks to analyze), and can only conclusively confirm use within the past month (not real-time detection). In the absence of a portable, non-invasive analytical tool to quantify marijuana intoxication, real-time THC sobriety tests rely heavily on subjective techniques that are prone to human error and/or bias. Consequently, these methods are inadequate for law enforcement, who need who need to quickly and accurately determine an individual’s state of impairment, and employers, who forbid “working under the influence”, but would allow responsible “off-duty” cannabis consumption to go unpenalized, so long as it does not affect job performance.Although there is no federal legislative consensus on the definition of marijuana intoxication, it is known that Δ9-Tetrahydrocannabinol (THC), the principle psychotropic in marijuana, has an approximate 3-hour detection window in the body that roughly correlates with symptoms of peak cannabis impairment. A small, but detectable, concentration of THC remains in equilibrium in the lungs during this 3-hour window, allowing the use of breath to be leveraged as a non-invasive method to determine recent cannabis consumption. After 3 hours, cannabinoid metabolites are rapidly diminished from the blood and lungs and absorbed into fatty tissue and the brain, reducing the efficacy of breath for use in non-invasive detection methods. While the low concentration of cannabinoids in breath ( µg/L – pg/L ) complicates detection, and there is ongoing debate as to how chronic marijuana use, gender, and body type affect baseline THC levels, there is a growing consensus that a breathalyzer will ultimately provide the best solution for a non-invasive, point-of-use detector for cannabis intoxication.Seacoast Science, Inc. is co-developing a hand-held marijuana breathalyzer in collaboration with Professors Nathaniel Lynd and Feng Zhang of UT Austin. This device will allow for the real-time, point-of-use detection and quantification of cannabinoids measured in the gas-phase. The underlying detection technology is based on the use of smart, biomimetic polymers with enhanced cannabinoid affinity measured by Micro-Electro-Mechanical Systems (MEMS) transducers (ie. chemicapacitors and chemiresistors). We will present results confirming reliable detection of a panel of gas-phase cannabinoids measured using this system in a controlled environmental chamber. The use of chemometric analysis to ...