Synthesis of Mn-doped CdTe quantum dots and their application as a fluorescence probe for ascorbic acid determination

A novel and highly sensitive fluorescence probe has been developed for determination of ascorbic acid (AA) based on the distinct fluorescence quenching of Mn-doped CdTe fluorescence emission in the presence of AA. Mn-doped CdTe quantum dots were prepared by using inorganic salts as precursors and L-cysteine as the stabilizer in an aqueous system. Their optical properties were characterized by ultraviolet-visible spectrometry, spectrofluorometry, structural features by X-ray diffraction spectrometry, transmission electron microscopy, Fourier transform infrared spectrometry, and exact composition by energy dispersive spectrometry, respectively. Under the optimum conditions, the response is linearly proportional to the concentration of AA in the range of 0.4 to 10 nM with an extremely low detection limit of about 0.081 nM. The newly developed method was successfully applied for the determination of AA in pharmaceutical tablets with good recoveries.