Electrochemical determination of ultralow levels (<10⁻¹² M) of mercury by anodic stripping voltammetry using a chemically modified electrode

A glassy carbon electrode (GCE) coated with 4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo[8.8.8]hexacosane, Kryptofix‐222, has been used for the very sensitive and selective analysis of very low levels of mercury. A detection limit lower than 10⁻¹² M (<0.2 ppt) was obtained applying anodic stripping voltammetry (ASV). The parameters that governed the sensitivity and possible interferences by other ions have been examined in detail. The electrode has been successfully applied for determining mercury in seawater, wastewater, and also in human saliva and amniotic fluid. The modified electrode exhibited high stability and, therefore, could be used repeatedly without mechanical regeneration.