Cysteine-Cystine Redox Cycling in a Gold–Gold Dual-Plate Generator-Collector Microtrench Sensor

Thiols and disulfides are ubiquitous and important analytical targets. However, their redox properties, in particular on gold sensor electrodes, are complex and obscured by strong adsorption. Here, a gold–gold dual-plate microtrench dual-electrode sensor with feedback signal amplification is demonstrated to give well-defined (but kinetically limited) steady-state voltammetric current responses for the cysteine-cystine redox cycle in nondegassed aqueous buffer media at pH 7 down to micromolar concentration levels. J.L.H. is supported by an U.K. Engineering and Physical Sciences Research Council (EPSRC) Doctoral Training Award. A.J.G. and F.M. gratefully acknowledge EPSRC funding (Grant EP/I028706/1).