半胱氨酸保护的荧光铜纳米簇快速检测对硝基苯酚

The Cysteine-Protected Copper Nanoclusters for Rapid Detection of p-Nitrophenol

对硝基苯酚(4-NP)是一种酚类化合物,具有致癌、致畸、致细胞突变的“三致”作用,成为全球关注的对象。以半胱氨酸保护的铜纳米簇(Cys-CuNCs)为荧光探针,采用4-NP和铜纳米簇的荧光猝灭效应,建立了一种新型、快速、准确、灵敏的荧光传感策略用于4-NP的检测。以抗坏血酸保护的非发光铜纳米粒子作为前驱体,采用半胱氨酸刻蚀法制备发光铜纳米簇。合成的铜纳米簇具有优异荧光性能和稳定性,在最佳激发波长370 nm激发下,于464 nm处发射出强烈的蓝色荧光。当体系中存在4-NP时,4-NP可明显猝灭铜纳米簇的荧光发射。以检测体系中缓冲溶液的pH、4-NP与铜纳米簇反应时间为单因素,优化检测4-NP的最佳分析条件,并建立相应的标准曲线。结果表明,最佳缓冲液体系为磷酸盐缓冲溶液(10 mmol·L^(-1) PB,pH 8.0);4-NP能够快速猝灭CuNCs的荧光,两者之间的反应仅需简单混匀即可进行荧光光谱扫描。以铜纳米簇荧光猝灭信号(F_(0)-F/F_(0))为纵坐标,4-NP浓度为横坐标,实现了4-NP的灵敏检测。4-NP浓度在1~100μmol·L^(-1)范围内呈良好的线性关系,线性回归方程为y=0.0042x+0.0162,检出限为0.31μmol·L^(-1)。选择4种其他4-NP同系物和8种其他有机物作为干扰物质,对铜纳米簇的荧光几乎都没有影响,表明该方法具有良好的抗干扰能力。此外,该方法在湖水实际样品检测中具有可行性,加标回收率为97.0%~101%,相对标准偏差(RSD)为2.71%~3.60%。说明该方法准确、可靠,有望用于实际环境样品中对硝基苯酚检测。

4-nitrophenol(4-NP),a phenolic compound with highly toxic and carcinogenic properties,has become a global concern.As a fluorescence probe,a rapid and sensitive fluorescence assay for 4-NP was developed using cysteine-protected copper nanoclusters(Cys-CuNCs).The Cys-CuNCs were prepared using ascorbic acid-capped copper nanoparticles(CuNPs)as a precursor and cysteine as an etching agent.The prepared Cys-CuNCs showed excellent fluorescence properties and stability solubility with the maximum excitation and emission peak at 370 nm and 464 nm,respectively.In the presence of 4-NP,the fluorescence of CuNCs was quenched effectively.Single-factor experiments were investigated to optimize the pH of the buffer and the reaction time for nitrophenol detection.The optimal conditions were as follows:phosphate buffer(10 mmol·L^(-1),pH 8.0)as a working buffer,mixing 4-NP and CuNCs for fluorescence scan.A sensitive analysis method for nitrophenol was constructed by utilizing the variation of fluorescence intensity F0-F/F0 as abscissa and 4-NP concentration as ordinate.The fluorescence quenching rate of CuNCs showed a linear relationship with the concentration of 4-NP in the range from 1 to 100μmol·L^(-1) with the detection limit of 0.31μmol·L^(-1).Four other 4-NP homologues and eight other organics were selected as the interferent;all of them had almost no effect on the fluorescence of CuNCs,indicating that the method had good anti-interference ability.In addition,the strategy was successfully applied to detect 4-NP in lake water with satisfactory recoveries from 97.0%~101%.The relative standard deviation was 2.71%~3.60%,indicating that the method is accurate and could be used for 4-NP detection in actual samples.