L-半胱氨酸包覆的ZnS:Mn²⁺水溶性的量子点荧光探针测定氟尿嘧啶的含量

目的: 以绿色环保材料为基础,在温和的条件下合成了水溶性的L-半胱氨酸包覆的锰离子掺杂的硫化锌量子点(L-Cys/ ZnS:Mn²⁺ QDs),并以此为荧光探针建立了测定抗癌药物氟尿嘧啶(FU)的新方法。 方法: 研究了FU对L-Cys/ ZnS:Mn²⁺ QDs荧光的淬灭作用并阐述了可能的作用机理。实验还考察了缓冲液体系、pH、反应时间、量子点浓度等多种因素对测定FU的影响。 结果: 在磷酸盐(pH 6.5)缓冲溶液中,L-Cys/ ZnS:Mn²⁺ QDs浓度为1.6×10^-4 mol·L^-1时,FU在1.0~85 μg·mL^-1的浓度范围内对量子点的荧光强度有较强的猝灭作用,且体系的荧光强度变化与溶液中氟尿嘧啶的浓度符合斯特恩方程,线性方程为:Y=0.01059C+0.9757(r=0.9988);猝灭常数为1.377×10³ L·mol^-1;检出限为 0.38 μg·mL^-1。将方法应用于实际样品FU注射液的分析,获得满意结果,FU的加样回收率为99.2%~100.0%。 结论: 该法简便、快速、灵敏度高,可望将其作为一种新型的荧光标记物用于体内药物的示踪和测定。

Objective: Mn²⁺ doped ZnS semiconductor quantum dots (QDs) have been synthesized using L-cysteine as surface modifying agent through a facile process in an aqueous solution.The QDs was then used to detect the fluorouracil (FU) as a fluorescence probe. Method: The effect of FU on the fluorescence intensity of L-Cys/ ZnS:Mn²⁺ QDs has been investigated.The reaction mechanisms were also been put forward.Some experiment conditions were studied such as the butter solution systems,the pH value and the concentration of QDs. Results: Under optimum conditions,the fluorescence intensity of QDs against the concentration of fluorouracil was linear over the concentration range of 1.0-85 μg·mL^-1 with an excellent 0.9988 correlation coefficient.The quenching constant could be obtained,which was 1.377×10³L·mol^-1 and the detection limit was 0.38 μg·mL^-1.The method has been applied to the determination of the fluorouracil injection with satisfactory results.The recoveries of spiked components of FU were 99.2%-100.0%. Conclusions: The method presented here is simple,rapid,sensitive and suitable for practical application.