Affinity of Electrochemically Deposited Sol–Gel Silica Films towards Catecholamine Neurotransmitters

Abstract

Dopamine, norepinephrine, and epinephrine neurotransmitters can be detected by electrochemical oxidation in conventional electrodes. However, their similar chemical structure and electrochemical behavior makes a difficult selective analysis. In the present work, glassy carbon electrodes have been modified with silica layers, which were prepared by electroassisted deposition of sol–gel precursors. These layers were morphologically and compositionally characterized using different techniques, such as field emission scanning electron microscopy (FESEM), TEM, FTIR, or thermogravimetric analysis–mass spectrometry (TG-MS). The affinity of silica for neurotransmitters was evaluated, exclusively, by means of electrochemical methods. It was demonstrated that silica adsorbs dopamine, norepinephrine, and epinephrine, showing different interaction with silica pores. The adsorption process is dominated by a hydrogen bond between silanol groups located at the silica surface and the amine groups of neurotransmitters. Because of the different interaction with neurotransmitters, electrodes modified with silica films could be used in electrochemical sensors for the selective detection of such molecules.

Simultaneous detection of dopamine, tyrosine and ascorbic acid using NiO/graphene modified graphite electrode

“…4(B) shows the CV p rofiles of DA at different concentrations and it is clear fro m the figure that the oxidation current of DA increases linearly with an increase in concentration at the NGM G mod ified electrode. The addit ional cathodic peak observed at 0.280 V is attributed to the reduced species of dopaminequinone in the solution [67]. 3.2.1.1.…”