Self-assembly of gold nanoparticles for the voltammetric sensing of epinephrine

A novel method for fabricating gold nanoparticles combining the dithiothreitol (DTT) and dodecanethiol (DDT) mixed self-assembled approach is proposed. The mixed self-assembled monolayers were first formed by the assembly of DTT and DDT from solution onto gold electrode. When these thiol-rich surfaces are exposed to Au colloid, the sulfurs form strong bonds to gold nanoparticles, anchoring the clusters to the electrode surface and a new nano-Au surface was obtained. In order to evaluate the electrochemical characteristics of nano-Au electrode, Fe(CN)63- was chosen as molecule probe and cyclic voltammetry (CV) was used. In addition, the functional nano-Au electrode was applied to the voltammetric sensing of epinephrine (EP). The nano-Au electrode is demonstrated to promote the electrochemical response of EP by cyclic voltammetry. The electrode reaction of EP is significantly improved at the nano-Au electrode which results in a large increase in the voltammetric peak current with a detection limit of 6.0 × 10−8 M and the diffusion coefficient D is as 7.40 × 10−5 cm2 s−1. The nano-Au electrode shows high electrocatalytic activity and excellent sensitivity property.