Antimony was reduced to Sb(III) with 5 ml of a solution containing
10% KI+10% ascorbic acid and 1mL of concentrated HCl. After addition
of the reduction solution to the water samples they were left for about
five minutes. Before the analysis was started an aliquot of the buffer solution
at the optimised concentration and pH was added (final volume:
50 mL). Blank solutions were prepared by application of the entire