Luminescence-based techniques for water quality monitoring

Water quality monitoring is a key aspect for providing and maintaining clean water supplies for the whole world. Water pollutants are many and heterogeneous in chemical nature so numerous sensing techniques and platforms are needed to provide a comprehensive analysis of water samples. In this context, sensors with an optical signal transduction mechanism can provide numerous advantages such as cost-effectiveness, ease of use, and rapid outputs. This PhD thesis describes three different approaches for the sensing of polluting chemical species relevant to water quality, employing luminescent based techniques. Detection of nonsteroidal anti-inflammatory drugs (NSAIDs), representing the category of “emerging pollutants”, was performed employing supramolecular fluorescent sensors capable of binging NSAIDs via hydrogen bonds and hydrophobic interactions in organic medium. Two different sets of sensors were developed, characterized and tested against common NSAIDs. Luminescent Eu(III) metal complexes were used to sense inorganic anionic species relevant to water quality monitoring. The peculiar photophysical properties of Eu(III) allowed us to obtain different outputs to different analytes; moreover, the high Lewis acidity of Eu(III) made the complexes able to bind anions in aqueous environment. An electrochemiluminescence-based immunosensor for the detection of Listeria was developed - in collaboration with Diatheva s.r.l. - as proof of concept, employing the architecture of an already existing immunoassay, to see how the assay’s performances could be enhanced, with minimal changes to the design. The architecture of the assay was adapted from a commercial ELISA developed by Diatheva and modified to be used in ECL, with the aid of magnetic micro-beads technology, obtaining promising results. Overall, this thesis presented valid optical-based sensing techniques applicable to environmental water quality monitoring. Moreover, this work represents a promising advancement in the field of sensing techniques development.