Rapid and selective fluorometric determination of tannic acid using MoO3-x quantum dots

The authors describe a fluorometric method for the quantification of tannic acid (TA). MoO_3-x quantum dots (QDs) can selectively capture TA via the formation of an organic molybdate complex. This causes an electron transfer effect and an inner filter effect to result in synergistic quenching of the fluorescence of the QDs. TA can be detected via this effect with a linear response in the of 0.1-10 μM concentration range and a lower detection limit of 30 nM within 1 min. The use of such QDs as a quenchable fluorescent probe warrants good selectivity even in the presence of relatively high concentration of potentially interferents and makes the method suitable for real sample analysis. Graphical abstract Tannic acid can be rapidly and selectively detected in food using a MoO_3-x quantum dots based fluorometric assay.