Electrochemically activated carbon fiber sensors as fast and sensitive adenine metabolite amperometric detectors

Abstract

A direct and fast voltammetric method of determination of 2,8-dihydroxyadenine (2,8-DHA), with a novel nanostructured carbon fiber sensor (CFS), is revealed in this work. To achieve high sensitivity required in biological determinations, before the determination of 2,8-DHA, carbon fiber sensors were activated by electrochemical pretreatment method. The electrochemical activation process generates a nanostructured carbon fiber surface, which is stable. The high stability of the active surface, and the high reproducibility of the activation process, leads to reproducible and sensitive fast scan voltammetric (FSV) determinations of 2,8-DHA. The 2,8-DHA sensitivity was determined in 31 mM phosphate buffer and Hank’s Balanced Salt solution (HBSS) : phosphate buffer (1:5) pH = 7.4, with different scan rates of 250, 500 and 1000 V/s. The potential window in the determinations was from -1.0 to 1.5 V (vs. SCE). A high sensitivity of the new method of 2,8-DHA determinations by FSV at 500 V/s was found to be 0.40±0.01 nA µM^-1 (r² = 0.998) from the calibration plot of 2,8-DHA, with a linear dynamic range from 1-20 µM, and a limit of detection of 1 µM under physiological conditions.