Arrays of Copper Microelectrodes from Disposable Chips: Fabrication and Characterization

A simple, fast, and low-cost process to fabricate arrays of copper microelectrodes (CuMEs) based on disposable electronic microchips is described. Arrays with 8 to 20 CuMEs were characterized by energy-dispersive X-ray spectroscopy and cyclic voltammetry techniques. The closest interelectrode distance in the arrays is 358 ± 22 µm, and the minor radius ranged from 10.6 to 13.5 µm. The microchips with CuMEs were sealed in epoxy resin to fabricate the rod and flat-shaped platforms, allowing the CuMEs to be addressed separately. Glucose, hydrazine, and nitrate were used as analyte models for voltammetric and amperometric detection at CuMEs arrays, showing excellent performance in batch and flow-through cells. Glucose measurements carried out with flow injection analysis system with amperometric detection at an array of 20 CuMEs showed a wide linear range (0.020-4.0 mmol L^-1), high sensitivity (734.1 µA L mmol^-1 cm^-2), and a limit of detection of 1.7 µmol L^-1.

Keywords:
copper microelectrode arrays; glucose; nitrate; electrochemical detection; flow analysis