Portable and affordable 3D-printed carbon-based electrochemical platform for voltammetric sensing of ivermectin

Ivermectin is an antiparasitic drug used to treat different forms of arthropod and nematode infection, not only in humans but also in domestic and farm animals [1]. In addition, it has antiviral characteristics for some viruses, which has led to abuse of its use in the treatment and prophylaxis of COVID-19, despite there being no significant data proving the drug's usability for this pathological agent [1]. In these circumstances, the development of affordable, portable, and sensitive analytical devices for ivermectin sensing is of great importance. We therefore propose a fully 3D-printed carbon-based electrochemical platform for the voltammetric determination of ivermectin. The proposed electrode consists of a material containing 40% w graphite (conductive material) and 60% w/w PLA (insulating component) extruded with a 3D pen onto a base previously 3D printed using resin (similar design to screen-printed electrodes). The sensor showed good inter-electrode reproducibility (relative standard deviation (RSD) = 2.3 %). Moreover, a square wave voltammetry method was developed offering a linear range of 0.1 to
1.5 μmol L-1, and limits of detection and quantification with values of 0.057 and 0.1 μmol L-1, respectively. Repeatability studies (consecutive measurements) confirmed the precision of the method (RSD= 4.0), while measurements in the presence of other antibiotics and excipient compounds certified selectivity. Thus, it can be concluded that the proposed strategy is valuable, low-cost, and easy to operate aiming at on-site monitoring of ivermectin levels.