Homi Bhabha National Institute, Mumbai, 400 094, India.
Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India.
Mikrochim Acta. 2019 Feb 15;186(3):183. doi: 10.1007/s00604-019-3292-1.
The authors describe the synthesis and characterization of 3-mercaptopropionylamidoxime functionalized gold nanoparticles (AuNPs) for visual detection of uranium (U) by cloud point extraction. The method is capable of quantifying U at the concentration limits set by the World Health Organization in drinking water i.e., 30.0 ng mL. The method is based on the gradual color change from red to blue that occurs as a result of the interaction between uranyl ion and the modified AuNPs leading to particle aggregation. Such analyte-triggered aggregation results in AuNP's peak absorbance quenching as well as red shift in the wavelength range of 520 to 543 nm. The colorimetric response at 520 nm is linear in the 2-100 ng mL U concentration range, and the limit of detection is 0.3 ng mL. No interferences by other ions are found, and the relative standard deviation is ≤4% (for n = 5). The method is validated by analyzing a certified reference material (NIST SRM 1640a; natural water), and also applied to the quantification of U in four (spiked) water samples. Graphical abstract Schematic presentation of cloud point extraction (CPE) assisted coloirmetric and visual detection of uranium (U). In CPE of gold nanoparticles (AuNPs) the color of surfactant rich phase (SRP) turns red in absence of U(VI) and blue in presence of U(VI).
作者描述了 3-巯基丙酰基氨肟功能化金纳米粒子（AuNPs）的合成与表征，用于通过浊点萃取法对铀（U）进行可视化检测。该方法能够定量检测饮用水中世界卫生组织设定的 U 浓度限值，即 30.0ng mL。该方法基于铀酰离子与修饰后的 AuNPs 相互作用导致颗粒聚集而发生的从红色逐渐变为蓝色的颜色变化。这种分析物触发的聚集导致 AuNP 的峰值吸收猝灭以及 520 至 543nm 波长范围内的红移。在 520nm 处的比色响应在 2-100ng mL U 浓度范围内呈线性，检测限为 0.3ng mL。未发现其他离子的干扰，相对标准偏差≤4%（n=5）。该方法通过分析认证参考物质（NIST SRM 1640a；天然水）进行了验证，还应用于四个（加标）水样中 U 的定量分析。
