Tetrakis (4-carboxyphenyl) porphyrin and Ru(bpy)32+ modified SiO2 nanospheres for potential and wavelength resolved electrochemiluminescence

Potential resolved electrochemiluminescence (ECL) nanoluminophores are very important for precise analysis and simultaneous determination of multiple targets. Designing ideal potential resolved ECL nanoluminophores, generating multiple high efficiency ECL emissions without overlap and interference of potential and wavelength, is a challenging subject. Herein, we developed a new nanoluminophore, meso-tetra (4-carboxyphenyl) porphine (TCPP)-functionalized chitosan/Ru(bpy)(3)(2+)/SiO2 (CRuSiO2) (TCPP@CRuSiO2), with cathode and anode ECL emissions by modifying TCPP on the surface of CRuSiO2 nanoluminophores. The TCPP@CRuSiO2 nanoluminophores presented a uniform sphere morphology (B50 nm). They exhibited two ECL emissions of 695 nm and 610 nm at -1.20 V and 1.15 V, respectively, by using K2S2O8 and tripropylamine (TPrA) as coreactants. Subsequently, the relevant ECL mechanisms are proposed. In the negative potential range, sulfate radicals (SO4 center dot-) reacted with TCPP-, generated by the electro-reduction of S2O42- and TCPP, to form the excited state TCPP*, resulting in ECL-1. In the positive potential range, Ru(bpy)(3)(3+) and TPrA(center dot), obtained by electro-oxidation of Ru(bpy)(3)(2+) and TPrA, reacted with each other to produce the excited state Ru(bpy)(3)(2+)*, leading to ECL-2. The synthesized TCPP@CRuSiO2 possesses not only potential and wavelength resolved ECL emissions, but also the advantages of easy synthesis, high ECL efficiency, good stability, and easy film formation on the electrode surface. This work enriches ECL nanoluminophores, which are of important application potential in precise analysis and multiplex analysis.

Automated summary

The development of potential resolved electrochemiluminescence (ECL) nanoluminophores is crucial for precise and multiplex analysis. In this study, a new nanoluminophore TCPP@CRuSiO2 was designed and synthesized, which exhibited both cathode and anode ECL emissions. The nanoluminophores had a uniform sphere morphology with a diameter of around 50 nm. They generated two ECL emissions at different potentials using K2S2O8 and tripropylamine (TPrA) as coreactants. The ECL mechanisms were proposed based on the reactions between different species. The synthesized TCPP@CRuSiO2 nanoluminophores not only possessed potential and wavelength resolved ECL emissions, but also showed advantages of easy synthesis, high ECL efficiency, good stability, and easy film formation on the electrode surface. This work enriches the study of ECL nanoluminophores and has important potential applications in precise and multiplex analysis.