Inhibitive determination of mercury ion using a renewable urea biosensor based on self-assembled gold nanoparticles

A renewable potentiometric urease inhibition biosensor based on self-assembled gold nanoparticles has been developed for the determination of mercury ions. Gold nanoparticles were chemically adsorbed on the PVC-NH2 matrix membrane pH electrode surface containing N,N-didecylaminomethylbenzene (DAMAB) as a neutral carrier and urease was then immobilized on the gold nanoparticles. The response characteristics of the DAMAB/PVC-NH2 pH-sensitive membrane and the effects of the size of nanoparticles have been investigated in detail. The linear range of determination of Hg2+ was 0.09–1.99 μmol L−1 with a detection limit of 0.05 μmol L−1. The advantages of self-assembled immobilization are low detection limit, fast response and ease regeneration. The assembled gold nanoparticles and inactive enzyme layers denatured by Hg2+ can be rinsed out via a saline solution with acid and alkali successively. This sensor is generally of great significance for inhibitor determination, especially in comparison with expensive base transducers.