2.2. Reagents
All solutions were prepared with doubly distilled water. Chemicals
used were of analytical grade and were purchased from E.
Merck (Darmstadt, Germany).
Stock standard solutions of Sb(V) were prepared by dissolving
the appropriate amount of potassium hexahydroxyantimonate(V)
in water. A stock solution of Sb(III) (1000 g mL−1) was prepared
by dissolving 93.5 mg of antimony chloride (III) in 5 mL hydrochloric
acid and diluting to the mark in a 50-mL volumetric flask. The
daily solution of the chelating agent was prepared by dissolving
the appropriate quantity of pyrogallol in water. Buffer solution
was prepared with appropriate amount of KCl 0.2 M and HCl 0.2 M