摘要
As one of most advanced transduction techniques,electrochemiluminescence(ECL),such as that generated by tris(2,20-bipyridyl)ruthenium(Ru(bpy)32þ),has been extensively used in chemical sensing and analysis,but the reaction mechanism has not been fully resolved.Aiming at gaining insightful mechanistic information on the coreactant system involving(Ru(bpy)32þ)and tri-n-propylamine(TPrA),herein we investigate the variation of thickness of ECL layer(TEL)with the concentration ratio of(Ru(bpy)32þ)to TPrA(cRu/cTPrA)by ECL microscopy.Using carbon fiber as the working electrode,TEL was observed to grow with the increase of cRu/cTPrA remarkably.In conjunction with finite element simulations,the extension of ECL layer was rationalized to be associated with the incremental contribution of so-called“catalytic route”.This route offers an additional channel of generating remote light emission in solution,apart from surface-confined emission produced by the“oxidative-reduction route”.Given the quantitative analysis of coreactant-type analytes is often based on the calibration curve,namely a graph generated by plotting the measured light intensity of a series of standard solutions against their concentrations,the contribution of“catalytic route”particularly at a low concentration of analyte(equivalent to a relatively large cRu/cTPrA)is favorable to the analytical sensitivity.Moreover,the presence and absence of this route will result in a nonlinear and linear calibration curve,respectively,for example in the detection of TPrA and pyruvate.The results highlight the microwire-based imaging approach can provide insightful mechanistic information and help unveil the concentration dependence of measured ECL intensity for precise quantitative analysis.
基金
support from the National Natural Science Foundation of China(22125405,22074131 and 21874117)is acknowledged.
