Nafion-coated cadmium pentacyanonitrosylferrate-modified glassy carbon electrode for detection of dopamine in biological samples

Introduction: Dopamine is one of the key neurotransmitters (NTs) in nature, which plays a crucial role in the mammalian central nervous system (CNS). Its selective determination in the biological fluids is an essential need in the field of biomedicine studies. Methods: In this work, an amperometric sensor was developed using Nafion-coated cadmium pentacyanonitrosylferrate (CdPCNF) modified glassy carbon (GC) electrode (Nafion|CdPCNF|GC electrode) as an electrocatalyst to detect dopamine (DA) in human serum samples. To develop this sensor, the surface of bare GC electrode was coated with the film of CdPCNF through an electropolymerization method and then the modified electrode was coated with Nafion to minimize interferences, especially those arising from the presence of anionic compounds. The electrocatalytic behavior of the modified electrodes was studied using the cyclic voltammetry and amperometry, and then the ability of the sensor for the determination of DA in synthetic and biological samples was investigated. Results: The modified electrode was showed a significant electrocatalytic activity for the oxidation of DA at pH 7.4. The limit of detection (LOD) was 0.7 µM and also no interference effects arose from ascorbic acid (AA), uric acid (UA) or the other biological NTs was observed in the DA detection using the modified Nafion|CdPCNF|GC electrode. Conclusion: In comparison with the bare electrode, the Nafion|CdPCNF|GC electrode could determine DA in the biological samples with adequate sensitivity and selectivity. Therefore, we propose that the modified electrode is utilizable as an amperometric DA sensor for the biological sample analysis.