Alternating Current and Direct Current Voltammetry with a Mercury Pool Electrode in Concentrated Hydrofluoric Acid

Polarography in media, such as hydrofluoric acid, in which glass is readily etched, is severely restricted because the dropping mercury electrode must be constructed from material other than that normally used, viz. glass. Voltammetry in concentrated hydrofluoric acid or anhydrous hydrogen fluoride at a mecury pool electrode in a cell based on a commercially available moulded Kel-F tube is simple, and provides a convenient alternative electroanalytical procedure to conventional polarography in media in which glass is etched. The reduction of thallium(I) has been investigated at a mercury pool electrode in about 50% HF by both ac and dc voltammetry. In this analytically important solvent, the limit of detection of thallium(I) was 5 × 10^-6M and 1 × 10^-6M by the ac and dc methods, respectively, with a reproducibility of ±2%. Ac and dc voltammetry in anhydrous hydrogen fluoride are also shown to be practicable.