Detection of Ascorbic Acid by Quantum Fluorescence Probe

CdTe quantum dots of highly fluorescent was prepared in aqueous solution with mercaptopropanoic acid(MPA) as stabilizer. The fluorescence of the CdTe QDs was significantly quenched with blue shift by the addition of Mn2+ due to the change of surface structure and chemical properties of the QDs. The fluorescence recovery was afterwards achieved in the presence of a small amount of ascorbic acid, which provided a novel QD-based turn-on fluorescent probe for the detection of ascorbic acid. When using QDs of 1.91 nm in size and a concentration of 1.67 mu mol/L in the presence of 0.25 mmol/L Mn2+, the recovered fluorescence was linearly related with the ascorbic acid concentration within 0.25-16 mu mol/L, with a detection limit of 36 nmol/L. The relative standard deviation was derived to be 2.6% at 10 mu mol/L of ascorbic acid (n = 11). The probe has been applied for the detection of ascorbic acid in V e tablets and human whole blood samples.