Diamond-derived microelectrodes array for electrochemical analysis

Two types of diamond electrodes were fabricated and characterized for electrochemical analysis; diamond ultramicroelectrode arrays (D-UMEAs) and nano-diamond-coated microprobes. Array parameters such as electrode geometry, electrode–electrode spacing, and array size are established through design and fabrication, and their relation to electrochemical analysis is evaluated. The superior detection figures of merit for diamond, particularly the limits of detection and sensitivity, have been achieved by shrinking electrode geometries with microfabrication techniques. The D-UMEAs were shown to display ultramicroelectrode (UME) behavior when individual active electrode was placed at a sufficient distance from each other. The D-UMEAs were also found to display higher current density for detection of analyte in comparison with a conventional diamond planar macroelectrode. Diamond ultramicroelectrodes in array configurations have potential applications in electrochemical analysis including the study of fast electron transfer reactions, electrocatalysis, and as a sensor in flow systems. The boron-doped nano-diamond-coated microprobe was fabricated with plasma-enhanced chemical vapor deposition (PECVD). The nano-diamond-coated microprobe showed good sensitivity to analytes with reversible electron transfer and a large potential window.