Toward an Optical and Electrochemical Method for Marijuana Detection: A Simple Electrochemical Oxidation of Δ9-THC

Marijuana has long remained one of the most commonly used illicit drugs in the United States and other countries. Recently, it has been estimated that 55 million Americans use this psychoactive drug, with growing usage being attributed to the legalization of marijuana in several states. A concerning implication of increased marijuana use is the alarming number of individuals who report driving under the influence of the drug. It is estimated that nearly 12 million people in the US alone have driven a vehicle while being under the influence of marijuana. To counterbalance the growing use of marijuana and potential associated dangers, it is imperative to develop detection technologies for marijuana usage. An electrochemical-based detection technology, akin to the alcohol breathalyzer, would provide an attractive solution to this growing societal problem. The first step toward this goal is to develop a fundamental reaction that converts tetrahydrocannabinol (THC), the primary psychoactive substance in marijuana, to a derivative with diagnostic spectroscopic changes. We report the development of a mild electrochemical method for the oxidation of THC to its corresponding p-quinone isomer. The photophysical and electrochemical properties of the resultant quinone show a dramatic shift in comparison to THC. This exceedingly simple protocol provides a foundational step toward the development of an electrochemical-based marijuana breathalyzer.