基于聚乙二醇非对称修饰金纳米粒子的铝离子比色检测方法

A Sensitive Colorimetric Detection Method for Aluminium Ion (Ⅲ) Based on Asymmetrically PEGylated Gold Nanoparticles

制备了聚乙二醇和柠檬酸钠不对称修饰的大尺寸金纳米粒子(AuNPs),利用柠檬酸根与Al^(3+)之间的螯合作用促使粒子发生定向团聚,实现了比色法检测Al^(3+),方法高效、准确、稳定。首先,制备不同粒径的柠檬酸钠修饰AuNPs(13、26和38 nm),考察了粒子尺寸与比色法检测Al^(3+)的灵敏度之间的关系,结果表明,增大粒径可显著提高检测灵敏度,其中38 nm AuNPs裸眼检测Al^(3+)的检出限可达1μmol/L;随后,将38 nm柠檬酸钠修饰AuNPs负载于载玻片上,利用载玻片表面掩蔽AuNPs表面部分位点,从而可在其余位点上不对称修饰惰性稳定基团聚乙二醇,通过激光动态散射仪、透射/扫描电镜、能谱仪表征了粒子表面结构。在此比色传感体系中加入Al^(3+)可实现AuNPs的定向和可控地聚集,形成的寡聚体在溶液中稳定存在。此体系响应信号与Al^(3+)在1μmol/L～100 mmol/L内呈良好的线性关系,线性方程为y=0.06485x+0.60851,(R^2=0.990)。此传感体系对Al^(3+)具有良好的选择性,常见金属离子不干扰检测,可应用于饮用水样品中Al^(3+)的检测。

An effective, accurate and stable colorimetric detection method for aluminium ion (Al^3+) through chelation based on the large-sized gold nanoparticles (AuNPs) asymmetrically modified with polyethylene glycol (PEG) and citrate was developed. Initially, citrate-stabilized AuNPs with different sizes (13 nm, 26 nm , 38 nm) were synthesized to explore the correlation between particle dimensions and detection sensitivity. The detection limit of 38 nm AuNPs was as low as 1 μmol/L by visual observation which demonstrated that sensitivity couold be improved by increasing the particle size. In the following, citrate-stabilized AuNPs were modified on the glass slide, through which some binding sites on the surface of AuNPs were concealed. The stabilizing agent PEG was introduced onto the exposed surface of AuNPs and characterized by laser dynamic scattering instrument (DLS), field-Emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and energy dispersive spectrum (EDS). The aggregation behavior was further adjusted in an oriented and controllable manner to form oligomers which could remain stable in aqueous solution for a long time. Such an asymmetrical modification could significantly improve the dynamic detection range (1 μmol/L–100 mmol/L), and a linear correction curve ( y =0.06485 x + 0.60851, R 2=0.99) was obtained. Nine common metal ions were also investigated, which exhibited the good selectivity of detection system to Al 3+. PEG and citrate modified AuNPs could be applied in the detection of spiked tap water sample.