Differential pulsed voltammetry of Δ9‐Tetrahydrocannabinol (THC) on disposable screen‐printed carbon electrodes: A potential in‐field method to detect Δ⁹‐THC in saliva

Abstract

Due to recent legalization of marijuana across many states in the U.S., there is an increased concern of users driving while impaired/intoxicated with Δ9‐tetrahydrocannabinol (Δ9‐THC), the principal psychoactive constituent of cannabis/marijuana. Hence, there is a need for a rapid roadside detection of this drug that can be used to accurately screen drivers. Current field sobriety tests rely on a series of physical and mental exercises administered during DUI investigations to help determine a driver's level of impairment. Due to their portability and effectiveness, screen printed carbon electrodes (SPCEs) are ideal to work with when it comes to devising a low‐cost screening device for roadside testing. SPCE's can potentially detect low levels of Δ9‐THC in an individual's saliva via electrochemical oxidation of Δ9‐THC. Herein we report a fast, cheap, and accurate approach to electrochemically detect 1–20 μM Δ9‐THC in a 1 mL sample of artificial oral fluid (AF‐OF) diluted to 50 % with a buffer/electrolyte solution using differential pulse voltammetry (DPV) at the surface of a small SPCE. Implications for the use of this method to screen intoxicated drivers are discussed.

Recent advances in the development of portable technologies and commercial products to detect Δ9-tetrahydrocannabinol in biofluids: a systematic review

“…Williams et al developed a simple method to detect THC at a concentration range of 1–20 μM in 50% diluted artificial saliva (with 0.1 M phosphate-buffered saline [PBS] at pH 11). They used screen-printed carbon electrodes (SPCEs) to electrochemically oxidize THC using DPV (Williams et al 2023 ). However, this device lacked sensitivity as the LOD reached 130 nM.…”