Smart Sensing for Antibiotic Monitoring in Mineral and Surface Water: Development of an Electronic Tongue Device

Sensors are considered the future monitoring tools, since, compared to traditional sampling and analysis techniques, they provide fast response on the output data in a timely, continuous, safe, and cost-effective fashion. Antibiotics are important pharmaceuticals with a large variety of applications. However, the overconsumption of these drugs is under the spotlight, since traces of antibiotics are being found in aquatic ecosystems and may lead to the development of antibiotic resistance. Thus, in this work, sensors consisting of ceramic or glass BK7 solid supports with interdigitated gold electrodes coated with five bilayers of polyethyleneimine (PEI) and poly(sodium 4-styrenesulfonate) (PSS) thin films were developed and able to distinguish clarithromycin concentrations between 10−15 M and 10−5 M in mineral and surface water matrices. In mineral water, the ceramic support sensors have shown high reproducibility, whereas glass support sensors are not reproducible for this matrix. For the surface water matrix, both types of sensors proved to be reproducible. The surface water’s principal component analysis, obtained for an electronic tongue composed of the aforementioned sensors, demonstrated the concept’s ability to discriminate between different concentrations of the target compound, although no significant pattern of trend was achieved.