Paper-based electrochemical sensor for simultaneous detection of salivary Δ⁹-tetrahydrocannabinol and thiocyanate to differentiate illegal cannabis smokers

Cannabis smoking is on the rise as a result of cannabis legalization across the world. The intake of cannabis by smoking has an impact on the mental health of smokers and intimates. Therefore, rapid monitoring of illicit cannabis use via direct saliva samples is necessary. The Δ⁹-tetrahydrocannabinol (Δ⁹-THC) and thiocyanate (SCN) level in saliva can be an effective biomarker to differentiate between cannabis and non-cannabis smokers such as cannabis ingestion, cigarette smokers, and healthy people. In this work, there is a development of an electrochemical sensor, “copper-phthalocyanine-modified screen-printed graphene electrodes (CuPc/SPGE),” for the concurrent determination of Δ⁹-THC and SCN using differential pulse voltammetry. Furthermore, the applicability of the CuPc/SPGE sensor was verified by simultaneously measuring Δ⁹-THC and SCN in saliva samples. The results from the developed sensor were similar to those obtained by high-performance liquid chromatography. This proposed sensor represents a first step in the differentiation of illegal cannabis smokers using the correlation between the contents of Δ⁹-THC and SCN in saliva, with features of rapidity, simplicity, low cost, and disposability.