An ascorbic acid sensor based on protein-modified Au nanoclusters

A simple fluorescence sensor for sensitive turn-off detection of ascorbic acid (AA) was developed by using protein-modified Au nanoclusters in aqueous media. The sensing mechanism is originated from the oxidation state change of Au nanoclusters controlled by AA. Under optimal experimental conditions, a good linear relationship between the relative fluorescence quenching intensity and the concentration of AA can be obtained in the range of 1.5 to 10 mu M, with a detection limit as low as 0.2 mu M. The proposed method is simple, efficient and reliable for monitoring of AA in some biological samples.