3D-printed electrochemical sensor for rapid nicotine detection in e-cigarette liquids and artificial sweat

Nicotine (NIC) is the main active component of tobacco used recreationally across the world. The absence of standardized guidelines for e-cigarette manufacturing has become a concern from the health community side. Herein, we have proposed a 3D-printed electrochemical sensor fabricated using a 3D printing pen to quantify NIC in e-cigarette liquids and sweat samples. All electrodes were fabricated using a commercial conductive filament containing Poly(lactic acid) and carbon black (PLA/CB) deposited in a poly(methyl methacrylate) (PMMA) platform. The electrochemical analysis were performed using 100 μL of the solutions and samples, without requiring any (electro)chemical pre-treatment. This feature increases the applicability of the 3D-printed electrochemical sensors. The electrochemical characterization shows that 3D-printed counter electrodes do not influence the current limitations. It provided an analytical performance comparable to other reports based on sophisticated electrochemical systems, with a linear sensing range from 4.9 to 162.2 mg L⁻¹; the LOD found was 2.7 mg L⁻¹. The sensor was successfully applied to quantify NIC in e-cigarette liquids and artificial sweat using simple dilution. Also, most sample components in these samples showed no interference with the NIC signal. The sensor presents key advantages, including low-cost, scalable fabrication and direct NIC detection without conventional electrode pre-treatment. Therefore, we believe this paper brings important insights that could assist regulatory agencies in monitoring NIC levels in e-cigarette liquids and sweat.