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

New fluorescent polysaccharides were synthesized by grafting the nucleobase adenine on to the backbones of agarose and κ-carrageenan, which were characterized by FT-IR, 13C 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 κ-carrageenan were recorded in aqueous (5 × 10−5 M) solution, exhibiting λem,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 × 10−5 M solution of the agarose and carrageenan grafted products, that is, 3.28 × 10−5 M and 4.5 × 10−5 M respectively. These fluorescent adenine grafted products may have potential utility in various sensor applications.