Abstract: Different approaches for increasing the sensitivity, selectivity and stability of a voltammetric probe for mercury ions have been investigated. These involve the application of adsorbed monolayers of a host molecule, i.e., 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (Kryptofix-222) and thin polymeric films. The stability, reproducibility and durability of the sensors in the analysis of Hg2+ from different sources have been examined and compared. We found that a monolayer of the macrocyclic ligand, which is capable of forming a strong and selective complex with the mercury, is superior to polymeric films in terms of sensitivity and ease of regeneration. On the other hand, the stability and durability of polymeric films, in which Kryptofix-222 is incorporated, will eventually dictate their use as preferred interfaces for repetitive analyzes especially in flow analysis systems. An application of a polymer-Kryptofix-222 modified electrode for monitoring mercury in a bioremediation pilot has been examined using an automatic sequential-injection stripping analysis (SISA) system. [Conference Paper; 4 Refs]

Abstract: A highly flexible, automatic sequential-injection stripping analysis (SISA) system has been developed and applied For monitoring the levels of mercury in aqueous solutions using a chemically modified electrode. The preparation of the modified electrode comprises spin coating of an ethanolic solution of poly(4-vinylpyridine) and Kryptofix-222 onto a glassy carbon electrode (GCE) followed by cross-linking the polymer. The analysis is based on the anodic stripping voltammetry of mercury using differential pulse voltammetry. A sequence of 36 operations was needed to complete a full cycle of cleaning, calibration and analysis.