Metal-Crown Ether-Porphyrin Decorated Gold Nanoparticles as High Sensitive Raman Ion Probe.

A kind of gold nanoparticles modified with metal crown ether porphyrin (GNPs-CP) was synthesized and characterized. The surface of the resulting gold particles was partially covered by metal crown ether porphyrin molecules through strong covalent Au-S bond. Based on the coupling effect of metal porphyrin and crown ether, the resulting composite gold nanoparticles can serve as a kind of ion probe. Raman and UV-Vis spectra were utilized to evaluate the ion recognition of the system, both of which changed dramatically when meeting metal ion corresponding to ligand of crown ether. Compared with UV-Vis spectra, Raman spectra of the composites are more sensitive and the limit of detection (LOD) can reach 1 × 10-8 g/mL. The study provides a candidate with higher sensitivity to replace current UV-Vis spectrum based evaluation tool for ion recognition.