One-pot synthesis of fluorescent polysaccharides: adenine grafted agarose and carrageenan

New fluorescent polysaccharides were synthesized by grafting the nucleobase adenine on to the backbones of agarose and kappa-carrageenan, which were characterized by FT-IR, C-13 NMR, TGA, XRD, UV, and fluorescence properties. The synthesis involved a rapid water based potassium persulfate (KPS) initiated method under microwave irradiation. The emission spectra of adenine grafted agarose and kappa-carrageenan were recorded in aqueous (5 x 10(-5) M) solution, exhibiting lambda(em,max) 347 nm by excitation at 261 nm, affording ca. 30% and 40% enhanced emission intensities, respectively compared to that of pure adenine solution in the same concentration. Similar emission intensity was recorded in the pure adenine solution at its molar equivalent concentrations present in the 5 x 10(-5) M solution of the agarose and carrageenan grafted products, that is, 3.28 x 10(-5) M and 4.5 x 10(-5) M respectively. These fluorescent adenine grafted products may have potential utility in various sensor applications. (C) 2012 Published by Elsevier Ltd.