Department of Applied Science, National Taitung University, 369, Sec. 2, University Rd., Taitung, Taiwan.
Sci Rep. 2020 Dec 4;10(1):21215. doi: 10.1038/s41598-020-78261-x.
In the present article, we report a novel colorimetric probe (TNT@MB) for the detection of the phosphate ion, which is based on the strong binding affinity between the phosphate ion and titanium dioxide nanotubes (TNTs). TNTs were synthesized from TiO nanoparticles by hydrothermal treatment. The obtained TNTs had an average length of 200 ± 50 nm and an average width of 12 ± 5 nm. TNT@MB was prepared by adsorbing methyl blue onto TNTs in acidic condition. The optimal synthesis conditions for TNT@MB consisted in having 0.05 g of TNTs react with 1 μmole of methyl blue at pH 2 for 90 min. TNTs and TNT@MB were characterized by UV-vis diffuse reflection spectroscopy, TEM, FTIR, and XPS. The phosphate-ion sensing behavior of TNT@MB was investigated by UV-visible spectroscopy. The phosphate-ion concentration linear range and detection limit of this method based on TNT@MB were 1-40 μM and 0.59 μM, respectively. A sample of lake water was used as a real sample, and analyte recovery rates were measured in the 102.5-103.6% range, with relative standard deviations below 5.6% (n = 3). We also found that this probe could be reused after regeneration in alkaline solution. These results indicate that as a colorimetric probe, TNT@MB has the advantages of being environmentally friendly, inexpensive, and simple to use, as well as giving rise to an easily observable color change.
在本文中，我们报道了一种基于磷酸根离子与二氧化钛纳米管（TNTs）之间强结合亲和力的新型比色探针（TNT@MB），用于检测磷酸根离子。TNTs 通过水热处理从 TiO2 纳米颗粒合成得到。所得 TNTs 的平均长度为 200 ± 50nm，平均宽度为 12 ± 5nm。TNT@MB 通过在酸性条件下将亚甲基蓝吸附到 TNTs 上制备得到。TNT@MB 的最佳合成条件是 0.05g TNTs 在 pH 2 下与 1µmol 亚甲基蓝反应 90min。TNTs 和 TNT@MB 通过紫外-可见漫反射光谱、TEM、FTIR 和 XPS 进行了表征。通过紫外-可见光谱研究了 TNT@MB 的磷离子传感行为。该方法基于 TNT@MB 的磷离子浓度线性范围和检测限分别为 1-40µM 和 0.59µM。以湖水样品作为实际样品，测定的加标回收率在 102.5-103.6%范围内，相对标准偏差低于 5.6%（n=3）。我们还发现，该探针在碱性溶液中再生后可以重复使用。这些结果表明，作为一种比色探针，TNT@MB 具有环保、廉价、使用简便以及易于观察到颜色变化等优点。
