A New Sensor with Increased Lifetime Based on a Mixed Diazonium Thick Film/Gold Nanoparticles Interface for Hg(II) Trace Detection

This work describes a novel strategy for surface functionalization, the aim of which is to significantly increase the lifetime of an electrochemical sensor dedicated to Hg(II) trace determination. In order to tailor stable mixed organic/inorganic interfaces, gold nanoparticles were electrodeposited onto a glassy carbon electrode previously functionalized by a thick 4‐thiophenol diazonium film, which affords a good anchoring to the nanoparticles. AFM and FEG‐SEM were used to characterize the film thickness and the nanoparticles average size and density, respectively. By using square wave anodic stripping voltammetry, the sensor exhibited a linear response between 1 and 10 nM Hg(II) and a normalized sensitivity 0.03 μA nM−1 min−1. Compared to previous works, the storage lifetime of the interface was at least three times longer, being more than three weeks.