A facile probe for d-fructose with fluorescence “on–off–on” switch ensemble

A highly selective switch for d-fructose was formed by a water-soluble fluorescent dye (HPTS) and boronic acid functionalized pyridine salt (m-P3BQ). The sensing ensemble shows high selectivity and sensitivity for d-fructose in aqueous solution. The construct of the sensing ensemble is facile and simple. The high selectivity of the sensing ensemble for d-fructose may be depended on suitable spacer width of boronic acid groups and a stable pyranose ester form of d-fructose with m-P3BQ. The research results can offer a new strategy to design and synthesize highly selective monosaccharides probes.