Fully integrated 3D printed device for the voltammetric determination of Δ9-THC and Δ9-THCA in Cannabis plants and extracts

With the legalization of medicinal or recreational use of Cannabis sativa L. and its derived products, there is a growing need to develop a sensitive, selective, and cost-effective method for the determination of the psychoactive cannabinoid Δ 9 -tetrahydrocannabinol (Δ 9 -THC) and its biosynthetic precursor, Δ 9 -tetrahydrocannabinolic acid (Δ 9 -THCA), in such samples. Herein, by harnessing the advantages of 3D printing technology—digital fabrication, simplicity, and affordability—we fabricated a compact, fully integrated 3D printed device, which was applied for the first time to the sensitive voltammetric determination of both cannabinoids. The plastic device was fabricated in a single step using a dual-extruder 3D printer and features three carbon black/polylactic acid (CB/PLA) electrodes (serving as working, reference, and counter electrodes) integrated into a small PLA cell. Under the optimized experimental conditions, the oxidation peak currents of Δ 9 -THC and Δ 9 -THCA showed a linear relationship with their respective concentrations, with limits of detection of 0.03 μM and 0.07 μM, respectively. The method demonstrated reproducibility below 9% for both within- and between-device measurements, indicating satisfactory operational and fabrication consistency. Finally, the integrated sensor was successfully applied to the determination of Δ 9 -THC and Δ 9 -THCA in Cannabis sativa L. plant material and cannabis extract samples, following a purification step using thin-layer chromatography. This compact, fully integrated plastic device can be easily produced at the points of need, enabling on-site routine determination of these key cannabinoids with high sensitivity and selectivity. • A 3D-printed integrated device was fabricated for Δ 9 -THC and Δ 9 -THCA determination. • The integrated device was fabricated in a single-step using a dual-extruder 3D printer. • Δ 9 -THC and Δ 9 -THCA levels in plant and extract samples were determined with the device. • The developed voltammetric method demonstrated high sensitivity and reproducibility.