Direct fluorimetric determination of ascorbic acid by the supramolecular system of AA with β-cyclodextrin derivative

We established a simple and selective fluorimetric method for the determination of ascorbic acid (AA) with the novel mono-[6-N(4-carboxy-phenyl)]-β-cyclodextrin (ACD). The method is based on the fluorescence intensity of ACD decreases as the ACD–AA supramolecular complexes form. The fluorescence intensity is measured at excitation and emission wavelengths of 270 and 352 nm, respectively. Under optimum condition, a linear relationship is obtained between the fluorescence intensity and the concentration of AA in the range of 0.05–8.0 μg ml−1. The detection limit is 0.012 μg ml−1. The method has been applied to the direct analysis of AA in real samples with satisfactory results.