Cellulose/amylose derivatives bearing bulky substituents as reversible fluorescent sensors for detection of Fe3+

Two novel cellulose and amylose derivatives bearing bulky tris(2-benzothienylformate) pendants ( Cel - 3 and Amy - 3 ) were expeditiously prepared by one-step esterification . The fluorescent sensing performance of six polysaccharide derivatives, including Cel - 3 / Amy - 3 , and other four previously prepared benzothienyl- or benzofuranyl-phenylcarbamates of cellulose and amylose ( Cel-1 / Amy-1 , Cel-2 / Amy-2 ), were carefully evaluated using eight metal ions , including Co 2+ , K + , Na + , Li + , Hg 2+ , Ni 2+ , Ca 2+ and Fe 3+ . All six derivatives exhibited excellent fluorescence quenching property to Fe 3+ ions with high sensitivity and selectivity. Especially, the limit of detection of Amy - 2 with benzofuranylphenylcarbamates for Fe 3+ was 3.0 μM, much lower than the maximum contaminant level for Fe 3+ in the drinking water . Additionally, the six bulky derivatives displayed the interesting fluorescence “turn-off” and “turn-on” observation, indicating a desirable reversibility for Fe 3+ detection. The high anti-interference ability was also observed for detection of Fe 3+ on the benzothienyl/benzofuranyl derivatives of cellulose and amylose in the combined system containing Co 2+ , K + , Na + , Li + , Hg 2+ , Ni 2+ and Ca 2+ . It suggested that the obtained polysaccharide derivatives with bulky chromophores possessed good potentials for detection of Fe 3+ as high-efficient fluorescent sensors in diverse applications. The sensing mechanism for detection of Fe 3+ was further proposed based on the Stern-Volmer plots and fluorescence titration analysis.