Electrochemical detection of nitrite and ascorbic acid at glassy carbon electrodes modified with carbon nano-onions bearing electroactive moieties

Identifier:  imarina:5131726

Handle: https://hdl.handle.net/20.500.11797/imarina5131726

Authors:  Bartolome, JP; Fragoso, A

Abstract:
In this work, we evaluate two novel surfaces for the simultaneous detection of nitrite and ascorbic acid in aqueous media. Glassy carbon electrodes were first modified with small carbon nano-onions (GCE/CNO) and further functionalized either by electrografting ortho-aminophenol (oAP) groups or by physical adsorption of thionine to give electroactive surfaces that were characterized by cyclic voltammetry. The modified surfaces exhibited a fast electrochemical response and were able to detect the presence of nitrite and ascorbic acid by amperometry. The presence of both CNOs and the electroactive moiety on the electrode surface enhanced the sensitivity and lowered the limit of detection of the determinations as compared to GCE modified only with oAP or thionine. The CNO-modified electrodes showed good reproducibility and stability with time and were applied in the detection of ascorbic acid in orange juice.