An ultrasensitive electrochemical method for rapid detection of mercury based on nanoporous gold capped with a novel Zr‐MOF‐SH/reduced graphene oxide aerogel composites

In this work, an ultrasensitive electrochemical sensor based on Zr‐MOF‐SH/rGA/NPG was developed for the first time for the rapid determination of mercury ions. First, nanoporous gold (NPG) film was covered on the glassy carbon electrode (GCE) to offer a desirable substrate. Then, Zr‐MOF‐SH/rGA composites were dropped on the NPG film to form a modified electrode. Mercapto functionalized MOFs (Zr‐MOF‐SH) showed strong adsorption capability toward mercury ions, and the unique structure of reduced graphene oxide aerogel (rGA) provided various sites for coupling with Zr‐MOF‐SH as well as improved the electrochemical activity. As a consequence of the synergistic effect of Zr‐MOF‐SH, rGA, and NPG, the optimized Zr‐MOF‐SH/rGA/NPG/GCE sensor showed excellent detection performance toward mercury ions with a linear range from 0 to 200 nM and a low limit of detection of 1.4 nM. Meanwhile, the fabricated electrochemical sensor exhibited outstanding stability, reproducibility, and anti‐interference ability. To verify the practical applicability, the Zr‐MOF‐SH/rGA/NPG/GCE was applied for the determination of mercury ions in real rice samples with desirable recovery rates ranging from 98.8% to 108.3%.