Reliability evaluation of nano-bi/silver paste sensor electrode for detecting trace metals

The reliability of sensor characteristics for a nano-bismuth (Bi)/silver (Ag) paste electrode has been investigated by comparison with Hg/Bi film electrodes in terms of accuracy and precision. Using Ag paste instead of carbon paste as a conducting layer, the sensitivity and detection limit of the sensor electrode were more enhanced due to a lower electrical conductivity of Ag. For the evaluation of detecting ability, the Zn, Cd, and Pb ion concentrations of the prepared standard solutions were experimentally measured on Hg film, Bi film, and nano-Bi electrodes using anodic stripping voltammetry. A nano-Bi electrode can detect Zn, Cd, and Pb ions at 0.1 ppb with higher precision and accuracy compared with Hg film and Bi film electrodes. From the trace analyses of Zn, Cd, and Pb ions in commercial drinking water and river water using a nano-Bi electrode and inductively coupled plasma (ICP) technique, it was concluded that the nano-Bi electrode exhibited excellent sensing characteristics with high reliability, and could detect even traces of Zn, Cd, and Pb ions that were not detected by the ICP method.