Simple strategy for the detection of the amoxicillin antibiotic in different matrices using a low-cost paper electrode

In this work, it is presented a simple and affordable method for the paper-based electrodes (PBE) manufacturing using a filter paper and conductive ink based on graphite and nail polish. Additionally, the disposable sensors were applied to the best of knowledge, in the first time for the electrochemical monitoring of amoxicillin (AMX) in complex samples as milk, pharmaceutical formulations, and synthetic urine by differential pulse voltammetry (DPV). Under optimized conductive ink composition, the AMX showed excellent electrochemical behavior on PBE surface with oxidation peak potential at +0.69 V (vs Ag|AgCl|KCl(sat.)) in phosphate buffer solution. Moreover, the proposed method presented a wide linear working range from 29.8 to 126.7 mu mol L-1 and adequate detectability (detection limit of 8 mu mol L-1). The electroanalytical measurements presented excellent precision with relative standard deviation less than 3% and good accuracy for the spiked samples ranging from 90 to 103%. In addition, the sensor did not undergo significant interference toward other commonly evaluated drugs, which demonstrates the potential of these electrodes for implementation in routine analysis and quality control.