SIGNAL STABILITY OF NAFION-COATED THIN MERCURY FILM ELECTRODES FOR STRIPPING VOLTAMMETRY

The signal stability of the Nafion-coated thin mercury film electrode (NCTMFE) was studied by using cadmium and lead as test analytes and di fferential pulse anodic stripping voltammetry as detection method. In particular, the effect of the casting solvent and the curing procedure employed in the preparation of the polymer film was examined. Best re sults were obtained with N,N-dimethylacetamide as casting solvent and a two-step curing procedure in which the polymer was evaporated to dry ness at 55-degrees and cured at 105-degrees with a hot-air gun. Mercur y plating was performed ex situ. An NCTMFE prepared in this manner has a better signal stability than ex situ-plated as well as in situ-plat ed conventional mercury film electrodes.