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Dopamine biosensor based on screen-printed electrode modified with reduced graphene oxide, polyneutral red and gold nanoparticle

ABSTRACT A new amperometric dopamine sensor has been developed on the basis of modified screen-printed electrode (SPCE) with reduced graphene oxide (RGO), polyneutral red (PNR) and gold nanoparticles (AuNP). The electrochemical behaviour of dopamine on SPCE/RGO/PNR/AuNP was investigated. The prepared sensor showed a high electrocatalytic effect on the oxidation of dopamine. In the amperometric determination of DA, optimum working conditions (optimum pH, optimum working potential, linear working range) were determined. The optimum values of these parameters in DA determination were 7.0 for pH and +0.25 V for working potential. The results of analytical characterisations, repeatability for 50 µM DA, sensitivity, the limit of detection, the limit of quantification and the linear range were found to be 2.14% (n = 10) as relative standard deviation (RSD.), 13.38 µA mM−1; 0.17 µM; 0.57 and 0.57–500 µM, respectively. Operational stability studies have shown that the initial amperometric response of the sensor to dopamine decreased by 90.05% on day 60. Storage life studies showed that the sensitivity of the biosensor decreased by 18.88% at the end of the 8th week. Amperometric electrochemical analysis of DA using SPCE/RGO/PNR/AuNP electrode was performed in the presence of interfering electroactive species AA and UA. The developed sensor was tested for DA determination in artificial blood serum samples.