水溶性蓝光发射金量子点灵敏检测L-半胱氨酸

Sensitive Detection of L-Cysteine by Using Blue Luminescent Gold Quantum Dots

室温下一步合成了一种蓝色发光金量子点。该金量子点具有良好的水溶性和生物相容性,金量子点平均粒径为3.0 nm,在波长305 nm光激发下,发射430 nm蓝色荧光。实验发现,一定量L-半胱氨酸对金量子点430 nm处荧光发射有显著的增强作用,由此可建立一种简单、迅速、灵敏检测L-半胱氨酸的新方法。在最佳条件下,金量子点荧光强度与L-半胱氨酸在0～4.0μmol/L浓度范围内呈线性关系,线性相关系数R2=0.9976,对2.0μmol/L L-半胱氨酸的11次测定结果的相对标准偏差(RSD)为2.8%,以3倍标准偏差计算本法对L-半胱氨酸测定的检出限为5 nmol/L。

Blue luminescent gold （Au） quantum dots （QDs） were facilely prepared through a one-pot synthesis at room temperature. The as prepared Au QDs were well water-soluble and biocompatable. The mean size of Au QDs is about 3.0 nm. Gold QDs colloids showed a considerable blue fluorescence emission at 430 nm under excitation of 305 nm. Experimental results demonstrated that the addition of L-cysteine could significantly enhance the characteristic emission of Au QDs at 430 nm. Therein, a simple, rapid, sensitive detection of L-cysteine in aqueous solution was established. Under optimized conditions, the characteristic fluorescence intensity of Au QDs at 430 nm is linearly proportional to the concentration of L-cysteine in the range of 0. 0 to 4. 0 × 10 -6 μmol/L and a detection limit as low as 5 nmol/L was obtained. The relative linear relationship coefficient is 0. 9976. The relative standard deviation for 11 replicate detections of 2.0μmol/L L-cysteine was 2.8%. In addition, this method also demonstrated a high selectivity to amino acids due to the strong affinity of L-cysteine to gold atoms.