A novel colorimetric chemosensor 1 was designed and synthesized for Fe^3+/2+ and pyrophosphate. Sensor 1 showed a selective color change toward both Fe³⁺ and Fe²⁺ from yellow to brown in a near-perfect aqueous solution. The detection limits (0.36 μM and 0.37 μM) for Fe³⁺ and Fe²⁺ were much lower than the guideline (5.37 μM) set by the Environmental Protection Agency (EPA) for iron in drinking water. Sensor 1 could be used to quantify Fe³⁺ in real water samples. Moreover, the resulting Fe³⁺-2·1 complex can detect pyrophosphate selectively over various anions especially including phosphate-based anions through a metal-complex displacement method. Based on UV-vis titrations, Job plot and ESI-mass spectrometry analyses, the sensing mechanisms of Fe³⁺, Fe²⁺ and PPi were proposed.

中文翻译：

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比色化学传感器在近乎完美的水溶液中 依次检测Fe ^{3 + / 2 +}和焦磷酸盐†

设计并合成了用于Fe ^{3 + / 2 +}和焦磷酸盐的新型比色化学传感器1。在接近完美的水溶液中，传感器1对Fe ³⁺和Fe ²⁺都有从黄色到棕色的选择性颜色变化。Fe ³⁺和Fe ²⁺的检出限（0.36μM和0.37μM）远低于环境保护署（EPA）所制定的饮用水中铁的准则（5.37μM）。传感器1可用于量化真实水样中的Fe ³⁺。此外，所得的Fe ³⁺ -2· 1配合物可以通过金属配合物置换法选择性检测各种阴离子，特别是包括基于磷酸盐的阴离子的焦磷酸盐。基于紫外可见滴定，Job图和ESI-质谱分析，提出了Fe ³⁺，Fe ²⁺和PPi的传感机理。