The concentration of Fe is determined in water samples by adsorptive stripping voltammetry with 1-nitroso-2-naphthol as complexing agent. All reagents have to be added in the order as listed below. All reagents typically contain iron impurities. Therefore a subtraction of the reagent blank is recommended. Fe(II) and Fe(III) show different sensitivities. Therefore the sample should only contain one of the iron species. Ascorbic acid (Vitamin C) can be added to the measuring solution and to the Fe(III) standard solution if both Fe(II) and Fe(III) are present in the sample to determine the concentration of total iron. A final concentration of ascorbic acid of 0.002 mol/L is suitable.