核壳纳米晶二硒化镉/硫化镉的合成及荧光法测定溶菌酶

Fluorescence Determination of Lysozyme with Cadmium Di-selenide/ Cadmium Sulfide Quantum Dots Synthesized in the Aqueous Solution

以3巯基丙酸为修饰剂,水相合成了具有发光效率高,光稳定性强等优良特性的CdSe2/CdS核壳纳米晶,粒径约为4nm,并将其成功用于溶菌酶的测定。在pH7.4的Na2HPO4NaH2PO4缓冲溶液中,以365nm激发,体系在642nm处的荧光强度与溶菌酶的浓度呈线性关系,线性响应范围为0.5～8.0mg/L和8.0～32mg/L;线性方程分别为ΔF=0.97+2.21C(mg/L)和ΔF=12.20+0.70C(mg/L);检出限为0.20mg/L。将该方法应用于样品的测定,结果令人满意。

Cadmium di-selenide/cadmium sulfide core/shell quantum dots (QDs) were synthesized and modified by 3-mercaptopropionic acid (MPA) in aqueous solution. In contrast with conventional organic dyes, these QDs are more brighter, more stable against photobleaching, and do not suffer blinking. The fluorescence intensity of these QDs is also more stable than MPA-capped CdS nanocrystals. The applicability of the results of these QDs to the determination of lysozyme was studied successfully. The pH value was selected at pH 7.40, with excitation and emission wavelength at 365 nm and 642 nm, respectively. Under optimal conditions, linear relationship was found between the relative fluorescence intensity and the concentration in the range of 0.5 similar to 8.0 mg/L and 8.0 similar to 32.2 mg/L for lysozyme (Lys) and the linear equation was Delta F = 0.97 + 2.21 C (mg/L) and Delta F = 12. 20 + 0. 70C (mg/L), respectively. The detection limit defined as three times of the standard deviation of the blank(3 sigma/K), of lysozyme is 0. 20 mg/L. And real samples were analyzed satisfactorily.