National Engineering Laboratory for Rice and By-products Further Processing, College of Food Science and Engineering, Central South University of Forestry & Technology, Changsha, 410004, China; Hunan Provincial Key Laboratory of Food Safety Monitoring and Early Warning, Changsha, 410004, China.
Hunan Edible Fungi Institute, Changsha, 410004, China.
Anal Chim Acta. 2021 May 22;1160:338380. doi: 10.1016/j.aca.2021.338380. Epub 2021 Mar 12.
The sensitivity for analytes of interest is vital for environment protection and food safety. Here, we propose an extremely sensitive assay toward Pb by using gold nanostars (GNSs) as probes based on the catalytic activity of Pb on etching gold atoms after being reduced in the presence of 2-mercaptoethanol (2-ME) and sodium thiosulfate. GNSs were prepared by using 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid as both the reducing and capping agents, enabling high stability and sensitivity for quantitation of Pb. Upon increasing Pb concentration over the range of 0-10 μM, GNS solution color changed from greenish-blue to blue to purple to red, and eventually to colorless. The color change can be distinguished by naked eye at the Pb concentration as low as 200 pM. Through monitoring longitudinal localized surface plasmon of GNSs, Pb could be detected with a limit of detection of 1.5 pM, and the working range is 2 pM-1 μM. The ultra-high sensitivity of our assay stems from the high catalysis of Pb on etching gold on tips and branches in the presence of 2-ME and sodium thiosulfate, leading to the shape deformation to spherical gold nanoparticle and the corresponding significant changes in their optical properties. The assay provides high selectivity of Pb over the tested interfering metal ions like Cu. With high sensitivity and selectivity, the assay was efficiently validated by analyzing water samples and monitoring the migration of Pb from the tested container to water.
分析物的灵敏度对于环境保护和食品安全至关重要。在这里，我们提出了一种基于 Pb 在 2-巯基乙醇（2-ME）和硫代硫酸钠存在下还原后对金原子进行蚀刻的催化活性，使用金纳米星（GNSs）作为探针来检测 Pb 的超灵敏分析方法。GNSs 是使用 4-（2-羟乙基）-1-哌嗪乙磺酸作为还原剂和封端剂制备的，这使其具有高稳定性和对 Pb 定量的高灵敏度。随着 Pb 浓度在 0-10 μM 范围内的增加，GNS 溶液的颜色从蓝绿色变为蓝色、紫色、红色，最终变为无色。在 Pb 浓度低至 200 pM 时，即可通过肉眼区分颜色变化。通过监测 GNSs 的纵向局域表面等离子体，我们可以用 1.5 pM 的检测限检测 Pb，工作范围为 2 pM-1 μM。我们的分析方法具有超高灵敏度，这源于在 2-ME 和硫代硫酸钠存在下，Pb 对尖端和支叉上的金进行蚀刻的高催化作用，导致形状变形为球形金纳米粒子，以及相应的光学性质发生显著变化。该分析方法对 Cu 等测试干扰金属离子具有高选择性的 Pb。该分析方法具有高灵敏度和选择性，通过对水样进行分析并监测测试容器中 Pb 向水中的迁移，对其进行了有效验证。
