Electrochemical sensors for fast classification of different Cannabis sativa L. samples according to total Δ9-tetrahydrocannabinol content
Alessandro Monari, Giorgia Foca, Alessandro Ulrici, Barbara Zanfrognini, Virginia Brighenti, Patrizia Verri, Federica Pellati, Chiara Zanardi, Laura Pigani
Abstract
In this work, we investigated the ability of an electrochemical sensor to recognize Cannabis sativa L. samples with different total content of Δ 9 -tetrahydrocannabinol (Δ 9 -THC), determined by the levels of the psychoactive cannabinoid and of its biosynthetic precursor Δ 9 -tetrahydrocannabinolic acid (Δ 9 -THCA), using a multivariate approach. The voltammetric responses recorded with screen-printed electrodes modified with carbon black reflected the compositional differences from the different samples, in terms of cannabinoids of the vegetal material. PLS-DA models allowed for the correct classification of most C. sativa samples into the classes of legal and illegal samples according to total Δ 9 -THC content, based on threshold limits defined by the EU/US (0.3 % w/w) and Italian (0.6 % w/w) regulations. Satisfactory results were achieved in both cases, obtaining classification efficiency values in prediction of the external test set equal to 85 % and 100 % for the EU/US and Italian thresholds, respectively. The obtained results suggest the possibility to consider the proposed method as a starting point for the implementation of an automated device for rapid prescreening of total Δ 9 -THC content directly on site. • Fast classification of legal and illegal Cannabis sativa L. samples is proposed. • 100 Cannabis sativa L. samples were analyzed by modified screen-printed electrodes. • Multivariate classification models were built according to Δ 9 -THC content. • Good classification results were achieved using legal limits of EU/US and Italy. • A device for rapid onsite prescreening could be implemented with this approach.