In-situ graft-crosslinked gold nanoparticles with high-density surface defects and coated with a polytaurine membrane for the voltammetric determination of dopamine

Abstract

Well-dispersed and graft-crosslinked gold nanoparticles (AuNPs) were synthesized by the reduction of tetrachloroaurate with hydrazine at room temperature. The AuNPs possess a high density of surface defects which is due to grafting of n-octanoic acid to polyvinylpyrrolidone. The physical and chemical properties of the resulting AuNPs were characterized by UV-vis, XRD, TEM/HRTEM, SAED, and XPS, respectively. The modified AuNPs were placed on a glassy carbon electrode (GCE) in an electropolymerized taurine layer to obtain a sensitive, selective, stable and rapid electrochemical dopamine sensor. The peak current, typically measured at 0.17V (vs. SCE), increases linearly in the 1.0 to 120μM dopamine concentration range, and the limit of detection (at S/N= 3) is 0.16μM with a sensitivity of 2.94μA·μM-1·cm-2. The sensor was successfully applied to the determination of dopamine in injections and spiked serum samples. The recoveries from spiked serum samples range from 97.5 to 102.4%, with RSDs ranging between 2.8 and 3.4%. Graphical abstract Schematic representation of a glassy carbon electrode modified with in-situ graft-crosslinkedgold nanoparticles combined with an electropolymerized polytaurine membrane. The sensor exhibits excellent features towards dopamine determination.