Selective fluorescent chemosensor for fructose

Abstract

A chemosensing system for the selective recognition of fructose based on a reverse photoinduced electron transfer process was developed. A fluorescent boronic acid, m-dansylaminophenylboronic acid, reacts with fructose to produce an electron transfer, which results in the fluorescence quenching of the dye. The addition of the sugar shifted the pK_a from 8.13 to 7.80. A possible sensing mechanism is proposed. The analytical figures determined in a batch approach were detection limit 5 × 10^–6M, repeatability of 1% at the 1 × 10^–4M fructose level and linear calibration up to 3 × 10^–4M. A flow injection system was also examined and after the experimental conditions had been optimized a selectivity study showed that only galactose (at a 1:2 fructose to galactose molar ratio) gave a positive deviation. Several food samples were analysed by the proposed flow injection procedure and the results agreed with those obtained using an enzymatic kit for food analysis.