Electrochemical oxidation of guanosine: Mechanistic insights and direct detection in weakly supported media

Guanosine, a purine nucleoside, is a potential biomarker of oxidative stress and central nervous system diseases. In this study, we investigate the oxidation of guanosine using a combination of voltammetric measurements at stationary and hydrodynamic electrodes, at both macro- and micro-scales, along with DFT calculations, shedding light on its complex reaction mechanism of significance in biological systems. In addition to providing mechanistic insights, we present the development of an electrochemical sensor for guanosine detection using a carbon fiber microelectrode. This sensor can be applied to samples with low ionic strength and exhibits two linear detection ranges in the absence of added supporting electrolyte: 0.0067 - 0.12 mM and 0.12 - 1.00 mM with the sensitivities of 1.40 +/- 0.03 nA mM-1 and 0.05 +/- 0.003 nA mM-1, respectively, and the limit of detection of (3sB/ m) 0.002 mM. The sensor was validated in synthetic urine samples, showing a %recovery of 99.71 +/- 4.02 % (RSD = 4.95 %), indicating its suitability for direct guanosine measurements in the complex matrices.

Automated summary

In this study, the oxidation mechanism of guanosine was investigated using voltammetric measurements and DFT calculations. An electrochemical sensor for guanosine detection was developed, and its reliability was validated in synthetic urine samples.