Sensor Based On Fluorescent Gold Nanoclusters To Detect Antioxidant

Gold nanoclusters are a kind of novel fiuorescent nanomaterials with many obvious advantages,such as facile preparation,good biocompatibility,low cytotoxicity and so on.Most of fluorescent gold nanocluster probes are based on fiourescence quenching.with some exceptions based on the fluorescence enhancement from the target.In our work we established two methods to detect antioxidant(take the case of ascorbic acid)based on the fiuorescence quenching and enhancement.In the first part of of this work,gold nanoclusters were synthesized with bovine serum albumin as both the template and reducing agent.When we added hydrogen peroxide and iodide ion,an obvious fluorescence quenching occurred.however,when ascorbic acid was added at the same time,the fluorescence was recovered.Thus a new antioxidant(take the case of ascorbic acid)sensor based on fluorescence restoration was developed.In the second part of this work,we established another method to detect ascorbic acid.The principle of the method is similar to the first approach.Iodine could render a significant quenching even under low concentration.When elemental iodine and ascorbic acid was added at the same time,the fiuorescece of gold nanoclusters recovered.Based on this we built another way to detect ascorbic acid.Because of its high sensitivity we applied this method to detect antioxidant(take the case of ascorbic acid)in fruits and beverages.The analyses of real samples verified the practical applicability of the sensor.