College of Chemistry, Nankai University, Tianjin 300071, China.
Dalton Trans. 2019 Mar 26;48(13):4168-4175. doi: 10.1039/c9dt00360f.
This paper reports the successful design of an UC fluorescence nanosystem for distinguishable and sequential detection of MnO4- and Cr2O72- based on the inner filter effect (IFE) between Gd2O3:Yb,Er upconversion nanospheres (UCNS) and 3,3',5,5'-tetramethylbenzidine (TMB). The detection of MnO4- was realized by a stoichiometric oxidation reaction between TMB and Mn(vii), which resulted in quenching of the upconversion luminescence (UCL) by the blue product through IFE. The assay of Cr2O72-, in contrast, was based on the formation of complexes and the consumption of the oxidation product of the previous reaction. The sensing of MnO4- did not interfere with that of Cr2O72- when Pb2+ was added as a masking agent. This provides a new strategy for sensitive and selective detection of MnO4- and Cr2O72-. The detection of MnO4- showed not only a low LOD of 0.243 μM but also high selectivity over other possible interfering ions. The sensitivity assay of MnO4- can be performed in the linear range of 1.85 to 69 μM. An excellent linear relationship was also found in the sensing of Cr2O72-, with a linear range of 18.3 to 250 μM and a LOD of 2.95 μM. The selectivity towards Cr2O72- was also proved to be good. Based on these properties, the UCNS-TMB nanoplatform is a potential chemosensor for both MnO4- and Cr2O72- ions in practical assays for waste water.
本文报道了一种基于 Gd2O3:Yb,Er 上转换纳米球（UCNS）与 3,3',5,5'-四甲基联苯胺（TMB）之间的内滤效应（IFE），成功设计了一种用于区分和顺序检测 MnO4-和 Cr2O72-的 UC 荧光纳米系统。TMB 与 Mn(vii)之间的化学计量氧化反应实现了对 MnO4-的检测，该反应导致通过 IFE 生成蓝色产物而使上转换发光（UCL）猝灭。相比之下，Cr2O72-的检测则基于络合物的形成和前一反应的氧化产物的消耗。当添加 Pb2+作为掩蔽剂时，MnO4-的检测不会干扰 Cr2O72-的检测。这为 MnO4-和 Cr2O72-的灵敏和选择性检测提供了一种新策略。MnO4-的检测不仅具有低检出限 0.243 μM，而且对其他可能的干扰离子具有高选择性。MnO4-的灵敏度检测可在 1.85 至 69 μM 的线性范围内进行。在 Cr2O72-的检测中也发现了良好的线性关系，线性范围为 18.3 至 250 μM，检出限为 2.95 μM。Cr2O72-的选择性也被证明很好。基于这些特性，UCNS-TMB 纳米平台有望成为实际废水分析中 MnO4-和 Cr2O72-离子的潜在化学传感器。
