Fluorescent detection of ascorbic acid based on the emission wavelength shift of CdTe quantum dots

We present a wavelength shift-based fluorescence detection method for ascorbic acid (AA) using CdTe quantum dots (QDs). Upon addition of ascorbic acid, the fluorescence emission peak of CdTe QDs red shifts linearly with the increase of the AA concentration, and the red shift speed could be improved by increasing the diameter of the QDs. The mechanism has been attributed to the AA-induced size change of the QDs. This AA-dependent red shift of fluorescence emission has been used to detect and quantify AA. Dynamic range and detection limit of this fluorescence probe are found to be 10-250 μmol/L and 1.3 μmol/L, respectively. Interference studies indicate that the AA could be specifically detected by using this wavelength shift-based fluorescence probe, and the QDs with larger diameter have better anti-interference performance. This fluorescence detection method is based on the wavelength shift of the emission peak, which is different from those reported traditional emission intensity-based fluorescent probes. Thus this fluorescence probe has the advantages of higher accuracy and convenient operation, which provides an effective strategy for design of wavelength shift-based fluorescence sensing method.