Glass supported SERS chips for emerging pollutant analyses

Abstract

The dramatic increase of environmental pollution leads to the demand of new sampling strategies that could perform in-situ monitoring and rapid identification. In this regard, Surface Enhanced Raman Spectroscopy is a good candidate among the possible analytical techniques. Thus, enormous efforts are in course to select best nanoplatforms able to maximize the SERS effect and in turn to reach the lowest limit of pollutant detection. In this work, we investigated the SERS response of colloidal gold nanostars (GNS) coated with a layer of silver with increasing thickness. In particular, we observed a maximum in the SERS signal at a precise silver thickness. The so-optimized GNS@Ag were used to prepare glass supported SERS substrates, displaying good enhancement factor and high homogeneity intra sample. We also evaluate the reproducibility on large-scale production, demonstrating again a good homogeneity of the response and the overall goodness of the substrates. Our glassy SERS-active chips were fruitfully used to detect norfloxacin and thiram, as representative of harmful and toxic pollutants.