Ratnarathorn Nalin, Chailapakul Orawon, Dungchai Wijitar
Department of Chemistry, Faculty of Science, King Mongkut's University of Technology Thonburi, Prachautid Road, Thungkru, Bangkok 10140, Thailand.
Center of Excellence for Petroleum, Petrochemicals, and Advanced Materials, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand.
Talanta. 2015 Jan;132:613-8. doi: 10.1016/j.talanta.2014.10.024. Epub 2014 Oct 23.
Highly sensitive colorimetric detection for Pb(2+) has been developed using maleic acid (MA) functionalized GNP. The -COOH on MA was used to modify GNP surface whereas the other -COOH functional group have strong affinity to coordination behavior of Pb(2+) allowing the selective formation more than other ions. MA-GNPs solution changed from red to blue color after the addition of Pb(2+) due to nanoparticle aggregation. The different optical absorption and discriminate of particle size between the MA-GNPs solution with and without Pb(2+) were characterized by UV-visible spectroscopy and transmission electron microscopy (TEM), respectively. The color intensity as a function of Pb(2+) concentration gave a linear response in the range of 0.0-10.0 µg L(-1) (R(2)=0.990). The detection limit was found at 0.5 µg L(-1) by naked eye and can be completed the analysis within 15 min. The MA-GNPs aggregated with Pb(2+) showed high selectivity when was compared to other metal ions (As(3+), Ca(2+), Cd(2+), Co(2+), Cu(2+), Fe(3+), Hg(2+), Mg(2+), Mn(2+), Ni(2+), Pb(2+) and Zn(2+)) and anions (Cl(-), NO3(-) and SO4(2-)). Our proposed method was also applied for the determination of Pb(2+) in real drinking water samples from 5 sources. The result of real water samples were not statistically significant different from the standard methods at the 95% confidence level (pair t-test method). Moreover, we evaluated our proposed method for the determination of trace Pb(2+) concentration in real breast milk samples. The recoveries were acceptable and ranged from 101 to 104% for spiked Pb(2+) in real breast milk samples. Thus, MA-GNP colorimetric sensing provides a simple, rapid, sensitive, easy-to-use, inexpensive and low detection limit for the monitoring of Pb(2+).
已开发出一种使用马来酸（MA）功能化的金纳米粒子（GNP）对Pb(2+)进行高灵敏度比色检测的方法。MA上的 -COOH用于修饰GNP表面，而另一个 -COOH官能团对Pb(2+)的配位行为具有很强的亲和力，使其能够比其他离子更具选择性地形成配位。加入Pb(2+)后，由于纳米颗粒聚集，MA-GNPs溶液从红色变为蓝色。分别通过紫外可见光谱和透射电子显微镜（TEM）对含有和不含有Pb(2+)的MA-GNPs溶液的不同光学吸收和粒径差异进行了表征。颜色强度随Pb(2+)浓度的变化在0.0 - 10.0 μg L(-1)范围内呈线性响应（R(2)=0.990）。通过肉眼发现检测限为0.5 μg L(-1)，且可在15分钟内完成分析。与其他金属离子（As(3+)、Ca(2+)、Cd(2+)、Co(2+)、Cu(2+)、Fe(3+)、Hg(2+)、Mg(2+)、Mn(2+)、Ni(2+)、Pb(2+)和Zn(2+)）以及阴离子（Cl(-)、NO3(-)和SO4(2-)）相比，与Pb(2+)聚集的MA-GNPs表现出高选择性。我们提出的方法还应用于测定来自5个水源的实际饮用水样品中的Pb(2+)。在95%置信水平下（配对t检验法），实际水样的结果与标准方法相比无统计学显著差异。此外，我们评估了我们提出的方法用于测定实际母乳样品中痕量Pb(2+)浓度。对于实际母乳样品中加标的Pb(2+)，回收率可接受，范围为101%至104%。因此，MA-GNP比色传感为监测Pb(2+)提供了一种简单、快速、灵敏、易于使用、廉价且检测限低的方法。
