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A novel method of carbon fiber microelectrode activation using spark discharge was demonstrated and compared to conventional electrochemical pretreatment by potential cycling. The spark discharge was performed at 800 V between the microelectrode connected to positive pole of the power supply and platinum counter electrode. Spark discharge led both to trimming of the fiber tip into conical shape and to the modification of carbon fiber microelectrode with platinum, as proven by scanning electron microscopy and electron dispersive X-ray spectroscopy. After the characterization of electrochemical properties using ferricyanide voltammetry, the activated electrodes were used for electrochemical analysis of 8-oxo-7,8-dihydro-2'-deoxyguanosine, an oxidative stress marker. Subnanomolar detection limits (0.55 nmol L-1) in high-performance liquid chromatography were achieved for spark platinized electrodes incorporated into the flow detection cell. (C) 2016 Elsevier B.V. All rights reserved.

We report a novel method for fabricating nanostructured copper-coated carbon cylindrical fiber microelectrodes and show the high efficiency of these electrodes in carbohydrate non-enzymatic and label-free amperometric sensing in both batch and flow-detection arrangements. This journal is © The Royal Society of Chemistry 2015.

A facile technique enabling CFMEs to be modified with nanostructured metal layers was developed. In this contribution, the approach is demonstrated for copper and bismuth. Copper modified CFMEs were employed in HPLC electrochemical detection of carbohydrates while bismuth coated CFME was used to detect nonsteroidal antiandrogens nilutamide and flutamide.