Department of Chemistry, Key Laboratory of Advanced Energy Material Chemistry, Ministry of Education , Nankai University , Tianjin 300071 , P. R. China.
Anal Chem. 2019 Apr 16;91(8):5455-5460. doi: 10.1021/acs.analchem.9b00848. Epub 2019 Apr 5.
pH value is a key parameter in reflecting the health status, reaction process, and water quality. The construction of highly sensitive pH luminescent ratiometric is important but challenging. Herein we designed and synthesized a unique triple-interpenetrated luminescent lanthanide-organic framework {[Eu(PPTA)(NO)(DMF)]·HO} (V104) based on an amphoteric ligand 4,4',4'',4'''-(1,4-phenylenebis(pyridine-4,2,6-triyl))tetrabenzoic acid (HPPTA). Compound V104 possesses high solvent and acid/alkaline stabilities. Luminescent investigations reveal that V104 exhibits dual emission peaks at 390 and 480 nm, and these two peaks can separately detect OH and H among various anions and cations. Importantly, V104 can serve as a self-calibrated pH ratiometric to quantitatively detect pH value, and the sensitivity can reach 403.2% per pH for OH, and 129.5% per pH for H. Furthermore, by encapsulating magnetic γ-FeO nanoparticles in V104, the pH sensor can be readily separated from the analyte by external magnet and recycled at least four times, suggesting as-synthesized γ-FeO@V104 has potential for monitoring pH fluctuations in water. To our knowledge, this is the first self-calibrated ratiometric pH-sensor based on two responsive wave bands which can separately detect OH and H.
pH 值是反映健康状况、反应过程和水质的关键参数。构建高灵敏度的 pH 值发光比率法非常重要，但具有挑战性。在此，我们设计并合成了一种独特的三重穿插发光镧系有机骨架{[Eu(PPTA)(NO)(DMF)]·HO}（V104），该骨架基于两性配体 4,4',4'',4'''-(1,4-亚苯基双(吡啶-4,2,6-三基))四苯甲酸（HPPTA）。化合物 V104 具有高溶剂和酸碱稳定性。发光研究表明，V104 在 390nm 和 480nm 处呈现出双发射峰，这两个峰可以分别检测到各种阴离子和阳离子中的 OH 和 H。重要的是，V104 可以作为自校准 pH 值比率法来定量检测 pH 值，对于 OH，其灵敏度可达每 pH 值 403.2%，对于 H，灵敏度可达每 pH 值 129.5%。此外，通过将磁性 γ-FeO 纳米粒子封装在 V104 中，pH 传感器可以通过外部磁铁从分析物中轻易分离出来，并可至少重复使用四次，表明合成的 γ-FeO@V104 具有在水中监测 pH 值波动的潜力。据我们所知，这是第一个基于两个响应波段的自校准比率法 pH 传感器，可分别检测 OH 和 H。
