量子点荧光探针检测抗坏血酸

以巯基丙酸（MPA）为稳定剂水相合成了高荧光CdTe量子点. 向量子点溶液中加入Mn2+，由于量子点表面状态发生改变而使其荧光淬灭，加入抗坏血酸后量子点荧光又得以恢复，且荧光恢复程度与抗坏血酸的浓度线性相关，从而建立了基于量子点的荧光“开关”探针检测抗坏血酸的新方法. 当CdTe量子点的浓度为1.67 uM（量子点的尺寸为1.91nm），加入的Mn2+浓度为0.25 mM时，在优化的实验条件下，检测抗坏血酸的线性范围为0.25~16 uM，检出限为36 nM. 相对标准偏差为2.5%(10 uM, n=11). 该探针可用于维生素C药片和人血浆中抗坏血酸的快速、灵敏和选择性检测.

Detection of Ascorbic Acid by Quantum Fluorescence Probe

CdTe quantum dots of highly fluorescent is prepared in aqueous solution with mercaptopropanoic acid (MPA) as stabilizer. The fluorescence of the CdTe QDs is significantly quenched with blue shift on the addition of Mn2+ due to the change of the surface structure and chemical properties of the QDs. The fluorescence recovery is afterwards achieved in the presence of a small amount of ascorbic acid. This provides a novel QD-based turn-on fluorescent probe for the detection of ascorbic acid. When using QDs of 1.91 nm in size and a concentration of 1.67 uM in the presence of 0.25 mM Mn2+, the recovered fluorescence is linearly related with the ascorbic acid concentration within 0.25-16 uM, with a correlation coefficient of 0.9980 and a detection limit of 36 nM. The probe has been applied for the detection of ascorbic acid in Vc tablets and human whole blood samples.