Study: Portable, Low-Cost Electrochemical Test Accurately Detects THC and CBD in Cannabis
- The study developed a portable electrochemical method using unmodified carbon screen-printed electrodes to simultaneously detect and quantify THC and CBD rapidly and inexpensively.
- Distinct oxidation and reduction processes for THC and CBD were identified via square wave voltammetry in alkaline medium, enabling clear differentiation without complex instruments or electrode modifications.
- The method showed low detection limits (0.09 μmol L⁻¹ for THC, 2.72 μmol L⁻¹ for CBD) with high precision and reproducibility, validated by analysis of seized cannabis samples and commercial products compared to GC-MS results.
- It successfully detected semi-synthetic cannabinoids without interference from CBD peaks and offers a reliable, field-deployable alternative for rapid cannabinoid screening useful to law enforcement and industry.
A new study published in the peer-reviewed journal Talanta details the development of a portable electrochemical method capable of simultaneously detecting and quantifying Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD), offering what researchers describe as a low-cost and field-deployable tool for fcannabis product quality control. The research was conducted by scientists from Universidade Federal dos Vales do Jequitinhonha e Mucuri, Universidade Federal de Mato Grosso do Sul, and Universidade Federal de Uberlândia. Their work centers on the use of unmodified carbon screen-printed electrodes in a strongly alkaline medium to distinguish and measure both cannabinoids in a single, rapid analysis.
Using square wave voltammetry, the team identified distinct oxidation processes for THC and CBD, enabling simultaneous detection without the need for expensive instrumentation or electrode modifications. THC exhibited a single irreversible oxidation process, while CBD demonstrated five well-defined electrochemical processes, including both reduction and oxidation events. Notably, the researchers report that CBD’s altered electrochemical behavior in alkaline conditions allowed for clearer differentiation from THC.
The method achieved limits of detection of 0.09 μmol L⁻¹ for THC and 2.72 μmol L⁻¹ for CBD. Precision testing showed strong reproducibility, with relative standard deviations below 5.6% for peak currents and under 2.0% for peak potentials when using either the same or different electrodes.
To validate real-world applicability, the researchers analyzed 35 seized cannabis samples and seven cannabis-based consumer products. Results showed good agreement with gas chromatography–mass spectrometry (GC-MS), the standard laboratory technique for cannabinoid identification. Addition-recovery experiments yielded values near 100% for both THC and CBD, further supporting accuracy.
The study also reports successful detection of structurally related semi-synthetic cannabinoids, including Δ8-THC, Δ8-THC acetate and hexahydrocannabinol (HHC), without overlapping CBD oxidation peaks. This is particularly relevant as semi-synthetic cannabinoids have become more prevalent in both retail markets and seized materials.
Unlike chromatography-based techniques, which require specialized laboratory equipment and trained personnel, this electrochemical approach is designed for rapid screening in field or high-throughput settings. The authors conclude that the method provides a reliable and practical alternative for law enforcement agencies and manufacturers needing fast, quantitative cannabinoid analysis.