Development of an electrochemical sensor to determine amoxicillin in natural water based on CORE-SHELL/PVP

In 2020, the world was affected by a new virus, SARS-CoV-2, which causes the disease known as COVID-19. Given the damage caused by the pandemic, there was a significant increase in the use of antibiotics. However, this increase causes harmful effects due to disposal in sewage systems by human and animal excretion and their manufacturing process. These drugs reach water resources, causing environmental impacts and damage. Given this current and worrying scenario, the focus of this work was to develop an alternative and lower-cost method for the detection of amoxicillin in natural urban waters, using an electrochemical sensor based on a core-shell formed by Fe3O4@Ag coated with the polymer polyvinylpyrrolidone. The device presented a wide linear range between 136 and 8210 µmol L-1 of amoxicillin, with a detection limit of 7.8 µmol L-1. When applied to detect the analyte in urban natural water samples and in commercial drugs, it presented a low relative error of 2.7% and 5.1%, respectively. Thus, the device proved to be an excellent alternative for detecting antibiotics in real samples, in addition to being miniaturized, allowing low-cost field analysis.