Turn‐on fluorogenic and chromogenic detection of cations in complete water media with poly(N‐vinyl pyrrolidone) bearing rhodamine B derivatives as polymeric chemosensor

A hydrophobic organic monomer GRBE with a polymerizable methacrylester moiety had been synthesized by reaction of rhodamine B-ethanediamine with glycidyl methacrylate. A water-soluble polymeric chemosensor poly(VP-GRBE) had been prepared via copolymerization with a hydrophilic comonomer (vinylpyrrolidone) and GRBE, which was able to sense environmentally poisonous cations in completely aqueous media. The chemosensor was a derivative of rhodamine B, which behaved as a fluorescent and chromogenic sensor toward various heavy cations, particularly Cr3+, Fe3+, and Hg3+. Titration curves of Cr3+, Fe3+, and Hg2+ were constructed using rapid, cheap, and widely available technique of fluorescence spectroscopies. The detection limits for Cr3+, Fe3+, or Hg2+ ions were found to be 2.20 x 10(-12), 2.39 x 10(-12), and 1.11 x 10(-12) mol/l in the same medium, respectively. Moreover, a colorimetric response from the polymeric chemosensor permitted the detection of Cr3+, Hg2+, or Fe3+ by "naked eye" because of the development of a pink or brown yellow color when Cr3+, Hg2+, or Fe3+ cations interacted with the copolymer in aqueous media. Copyright (C) 2015 John Wiley & Sons, Ltd.