Simultaneous Voltammetric Determination of Zn, Cd and Pb at Bismuth Nanopowder Electrodes with Various Particle Size Distributions

Effect of particle size distribution on sensor characteristics of nano-Bi fixed electrode has been investigated using square wave anodic stripping voltammetry. Bi nanopowders with various particle size distributions were synthesized by gas condensation (GC) method with the change of chamber pressure. As the chamber pressure decreased, the size of Bi nanopowder became smaller with narrower distribution due to a shorter residence time of Bi vapor. The square wave anodic stripping voltammograms (SWASV) showed well-defined and highly reproducible peaks at −1.2 V, −0.8 V and −0.6 V (vs. SCE), which are closely related to the oxidation of Zn, Cd and Pb, respectively. The sensitivity and detection limit of the nano-Bi fixed electrode were quantitatively estimated from the analyses of SWASV. From the results, it is concluded that as the size of Bi nanopowder becomes smaller with narrower particle size distribution, the sensitivity and detection limit of sensor electrode for Zn, Cd and Pb are improved, which is ascribed to the increase in electrochemical-active surface area.