ventional PSA to those analytes that cannot
be deposited cathodically owing to their low
solubility in mercury or markedly cathodic
half-wave reduction potentials. Such elements
may occasionally be preconcentrated
anodically and determined by cathodic stripping
voltammetry. In addition, interferences
may be overcome in some favorable cases
by switching from anodic to cathodic stripping
analysis. The RPSA technique was first
implemented by Christensen and Kryger12
using the determination of manganese as
chemical model; the metal was preconcentrated
by anodic oxidation at a platinum
electrode and stripped by using hydroquinone
as reductant (Figure 9). In this way, manganese
was determined at concentrations in the
microgram per milliliter range. The accuracy
of the technique, tested on a standard
biological material, is quite satisfactory.