Simultaneous determination of paracetamol and caffeine in pharmaceutical formulations and synthetic urine using cork-modified graphite electrodes

Cork-modified graphite electrodes were used to develop a simple and selective sensor for the simultaneous determination of paracetamol (PAR) and caffeine (CAF). The sensor was fabricated on raw cork (RAC) and regranulated cork (RGC). When modified with RAC, graphite (GrRAC) displayed an improvement in voltammetric responses for PAR and CAF compared to the sensor modified with RGC (GrRGC). By applying differential pulse voltammetry (DPV) in an acidic medium with the GrRAC sensor, it was possible to simultaneously determine the concentrations of PAR and CAR (ranging from 0 to 50 μM), with limits of detection of 8.36 and 12.25 μM, respectively. The fabricated electrochemical sensor was able to individually and simultaneously detect PAR and CAF in different samples, confirming that the proposed sensor is a practical and effective tool for determining these pharmaceuticals in dosage forms and synthetic urine. Moreover, GrRAC and GrRGC possessed several advantages compared with current methods of detection, including very low detection limits, high sensitivity, long-term stability, and excellent reproducibility.