For fast and visual detection of multiple metal ions, herein, a re-usable colorimetric polymeric gel with spiropyran moiety was fabricated. Under ultraviolet light, the spiropyran (SP) moiety could isomerize into the colored merocyanine (MC) isomer and chelate with divalent metal ion (M²⁺) and form MC-M²⁺ complexes. Chelated with different metal ions (Ca²⁺, Co²⁺, Zn²⁺, and Cu²⁺ions), the UV–Vis spectra of the gels could display the specific colorimetric response. When the metal-ions chelated gel was irradiated with Vis light, ions dissociated from MC and released from gel due to the MC moiety isomerized to the SP form. Furthermore, after 7 cycles of alternative UV–Vis irradiations, the gel showed excellent reversible chelation/dissociation of metal ion. The competitive tendency of metal ions to chelate with gel was as following: Cu²⁺ > Co²⁺ ≈ Zn²⁺ > Ca²⁺, which was in accordance with the density functional theory modeling. Using ionoprinting technology, the gel could achieve repeatability simultaneous detection of multiple metal ions. The light-triggered metal ion chelation/dissociation capability of the gel could be harnessed to construct reusable onsite platform for visual, fast, easy detection of multiple metal ions.

为了快速和可视地检测多种金属离子，本文制备了具有螺吡喃部分的可重复使用的比色聚合物凝胶。在紫外光下，螺吡喃（SP）部分可以异构化为有色的花菁（MC）异构体，并与二价金属离子（M ²⁺）螯合，形成MC-M ²⁺络合物。与不同的金属离子（Ca 2 ⁺，Co 2 ⁺，Zn ²⁺和Cu ²⁺离子），凝胶的UV-Vis光谱可以显示特定的比色响应。当用Vis光照射金属离子螯合的凝胶时，由于MC部分异构化成SP形式，离子从MC解离并从凝胶中释放出来。此外，经过7次交替的UV-Vis照射后，凝胶显示出极好的可逆的金属离子螯合/离解。金属离子与凝胶螯合的竞争趋势如下：Cu ²⁺  > Co 2 ⁺  ≈Zn ²⁺  > Ca ²⁺，这符合密度泛函理论建模。使用电离印刷技术，该凝胶可以实现重复性，同时检测多种金属离子。可以利用光触发的金属离子螯合/解离能力来构建可重复使用的现场平台，以可视，快速，轻松地检测多种金属离子。