Functional modification of agarose: A facile synthesis of a fluorescent agarose–guanine derivative

A new fluorescent polymeric material was synthesized by grafting the nucleobase guanine on to the backbone of agarose. The synthesis involved a rapid water based method under microwave irradiation using potassium persulphate (KPS) as an initiator. The emission spectrum of the modified agarose recorded in 0.1 M aqueous NaOH (5 × 10−5 M) solution exhibited emission maxima (λem,max) at 340 nm by excitation at 274 nm. The emission intensity was enhanced by ca. 85% compared to that of pure guanine solution of the same concentration. When the concentration of the pure guanine solution is made equivalent to the concentration of the guanine molar component (3.63 × 10−5) present in 5 × 10−5 M solution of modified agarose, then ca. 105% enhancement in emission intensity was observed. The remarkable fluorescent activity of the agarose–guanine derivative may have potential uses as sensor in various applications.