超分散石墨相氮化碳纳米片的制备及其在抗坏血酸传感检测中的应用研究

s a novel polymer semiconductor, graphitic carbon nitride (g-C3N4) has attracted much research attention in the field of catalysis and biosensing due to its unique properties. In this study, ultra-dispersed g-C3N4 nanosheets was prepared by using thiourea and tyrosine as precursor through microwave method. An "on-off-on" fluorescent biosensors was constructed with g-C3N4 nanosheets as fluorescent probe, in combination with Cu2+, to achieve fluorescence sensing analysis of ascorbic acid. The effects of Cu2+ concentration and pH value of the buffer solution on the detection results were optimized. The linear range is 0.2-2 nmol/L and the detection limit is 0.14 nmol/L under the conditions of pH 7.8 and Cu2+ concentration of 1 μmol/L. Commonly encountered anions，cations and reductive materials that similar to ascorbic acid do not interfere much with the biosensor. The method has been applied to the analysis of ascorbic acid in commercial fruit juice with satisfactory results.