Luminescent Lanthanide-Based Sensor for H2O Detection in Aprotic Solvents and D2O

Applied methods for detecting water impurities in organic solvents, such as Fischer titration, include wayward equipment and toxic reagents. This method is inapplicable for detecting H ₂ O in D ₂ O, but suitable techniques like NMR-, IR-, and mass-spectrometry are costly. We report a low-cost, novel luminescent sensor material based on terbium-europium 3D MOF compound developed for facile, portable, and disposable monitoring of water quantities. Our sensor is able to determine water traces in D ₂ O and aprotic organic solvents. Treating the material to solvent leads to the change in intensities ratio of terbium and europium bands in emission spectra depending of water content and nature of solvent. For D ₂ O calibrating plot $\text{I}_{\mathrm {Eu}}/\text{I}_{\mathrm {Tb}}$ –%H ₂ O is linear whereas for dioxane and acetonitrile the dependence becomes linear in the coordinates $\text{I}_{\mathrm {Eu}}/\text{I}_{\mathrm {Tb}}$ -ln(%H ₂ O). The results reveal the potential application of developed sensor for ratiometric quantitation of H ₂ O admixtures in D ₂ O, organic solvents, transformer oil, etc.