The acids and bases of extreme concentrations (c > 0.1 mol
dm3) are unsuitable for amperometric determination due to the
difficulty to keep constant ionic strength in a given supporting
electrolyte solution, as well as due to an inappropriately high limiting
current densities, accompanied by extensive hydrogen deliberation
in acids and extensive anodic dissolution of tungsten in
alkalis. To avoid these problems, one may use the method of standard
additive. Namely, once the calibration curve jL vs.