Flexible electrodes based on laser-induced graphene as an analytical platform to monitor amoxicillin

Graphene production methods are typically complex and include micromechanical exfoliation, reduction of graphene oxide in the liquid phase, and epitaxial growth. However, a more efficient and rapid alternativeis the thermal conversion of polyimide into graphene via laser pyrolysis, offering a simpler and faster approach. Thus, this paper introduces an electrochemical platform based on laser-induced graphene generated from a visible light source to detect amoxicillin. For this purpose, a laboratory-constructed 3D-printer was utilized. In this setup, a visible laser source emitting at 449.2 nm with a maximum power output of 3.5 W was integrated into the extrusion nozzle of a fused deposition modeling 3D-printer to manufacture graphene electrodes from polyimide sheets. Subsequently, a differential pulse voltammetry method was proposed showing an oxidation peak at +0.52 V (vs Ag|AgCl|KCl_(sat.)). The sensor exhibited a wide linear working range from 9.60 to 103.3 µmol L⁻¹, a limit of detection of 4.9 μmol L⁻¹, adequate precision (RSD < 7%), and recovery values of 90% to 107% when applied to milk samples, synthetic urine, and pharmaceutical formulations. The sensor is free from interference with other drugs commonly used in human and veterinary medicine. Herein, we report for the first time a robust, scalable, and inexpensive sensor based on a flexible substrate for the detection of amoxicillin in different matrices. It stands as an accessible possibility for routine analysis in clinical and pharmaceutical contexts.