Simultaneous determination of dopamine and folic acid using chitosan-carrageenan hydrogel/graphene oxide modified glassy carbon electrode

Dopamine and folic acid are compounds that coexist in biological fluids, essential for metabolic processes and central nervous system function. The fast, sensitive, and accurate detection of these compounds in biological and pharmaceutical samples holds significant importance for human health assessment and the pharmaceutical industry. An innovative and efficacious electrochemical sensor for the simultaneous quantification of dopamine and folic acid was developed. This sensor was based on the glassy carbon electrode modified with chitosan kappa- carrageenan hydrogel, enriched with the addition of a catalytically active component - graphene oxide. This modification procedure significantly improved the adsorption of the analytes onto the electrode surface thanks to the established favorable intermolecular interactions, thereby enhancing the electrical conductivity of the electrode. The sensor demonstrated an extensive linear response range of the cathodic current in relation to the concentration of dopamine and folic acid, both when quantified individually and simultaneously. Key advantages of this sensor include the obtained low detection limits for both analytes (5.65 x 10(-9) mol/L for dopamine, and 1.88 x 10(-7)mol/L- 7 mol/L for folic acid), electrode selectivity, stability, and good reproducibility of results. The results achieved in this study signify the considerable potential of the developed sensor for the determination of dopamine and folic acid in diverse sample types. Additionally, this work presents an effective method for sensitive detection of selected analytes, and also highlights the utilization of nontoxic compounds in the preparation of a biocompatible sensor, given its considerable potential for future practical applications in various fields.