A turn-on fluorescent probe for phytic acid based on ferric ion-modulated glutathione-capped silver nanoclusters

Abstract

In this work, we describe a method for the fluorometric determination of phytic acid (PA) by using glutathione-capped silver nanoclusters (GSH@AgNCs). This method is based on the finding that ferric ions (Fe³⁺) can quench the fluorescence of GSH@AgNCs. PA, a kind of multiphosphate with a high density of negatively charged phosphate groups, shows a strong affinity for Fe³⁺ ions due to the multiple ligands. As a result, the presence of PA can prevent the quenching of the fluorescence of GSH@AgNCs by Fe³⁺ ions thus resulting in the turn-on fluorescence of GSH@AgNCs. The developed fluorimetric analysis method can allow the detection of PA with a detection limit of about 1.0 μM. Furthermore, this method was also successfully applied to the determination of PA in spiked corn grain samples with satisfactory recoveries in the range of 91.4–107%.