Quadruple nanoelectrode assembly for simultaneous analysis of multiple redox species and its application to multi-channel scanning electrochemical microscopy.

Development of ultramicroelectrodes and nanoelectrodes opened interesting possibilities in the investigation electron transfer phenomena, including their application as probe electrodes in scanning electrochemical microscopy (SECM). Analytical prowess of SECM was often shadowed by long operation times required for analysis of a wide sample area. In this report, we developed a multi-channel nanoelectrode bundle for simultaneous electroanalysis of multiple orthogonal redox reactions in one bath. Four nanoelectrodes of diameters 100-400 nm were shown to be bundled in a 2 μm disk area. The nanoelectrode assembly was implemented as a tip electrode for multi-channel SECM, dramatically improving the time efficiency of SECM operations. The nanoelectrode bundle was also demonstrated as a stand-alone microprobe for electroanalytical investigations in small volumes such as ceramic confinements and biologically important compartments. The development reported in this work should benefit electrochemical analyses of various systems, especially those involving SECM and fine spatial control.