Chromogenic and fluorogenic detection of cations in aqueous media by means of an acrylic polymer chemosensor with pendant Rhodamine-based dyes

A water-insoluble organic chemosensor has been chemically modified by introducing a polymerizable methacrylamide moiety via copolymerization with a hydrophilic comonomer (vinylpyrrolidone), producing a water-soluble acrylic copolymer that is able to sense environmentally poisonous cations in pure aqueous media. The chemosensor is a derivative of Rhodamine B, which behaves as a fluorescent and chromogenic sensor toward various heavy cations, particularly Hg(II). Titration curves of Hg(II) were constructed using rapid, cheap, and widely available techniques, such as fluorescence and UV/Vis spectroscopies. Furthermore, a colorimetric response from the copolymer chemosensor permitted the detection of Hg(II) by eye due to the development of a pink color when this cation interacted with the copolymer in aqueous media.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights▶ A chromogenic and fluorogenic copolymer chemosensor has been prepared. ▶ The sensory material permits the detection and quantification of mercury cations. ▶ The sensory motif, a Rhodamine dye, was hydrophobic and insoluble in water. ▶ However, the prepared copolymer was highly hydrophilic and water soluble. ▶ This methodology allows the exploitation of water insoluble organic dyes in water.