A
Highly Sensitive Spectrophotometric Method for the Determination of
Iodate Using
Leuco Xylene Cyanol FF
Chand Pasha and B. Narayana*
Department of Post Graduate Studies and Research in ChemistryMangalore University, Mangalagangothri – 574 199,Karnataka, India .* E-mail: nbadiadka@yahoo.co.uk , Fax: 0091-824-2287367Abstract
A highly sensitive and selective spectophotometric method has been developed
for the determination of iodate (IO3-) in table
salt and sea water. The proposed method is based on the oxidation of leuco
xylene cyanol FF (LXCFF) to its blue form of xylene cyanol FF by iodate in
sulfuric acid medium, the absorbance of the dye is measured in an acetate buffer
medium (pH 4.0) at 620 nm. Beer’s law is obeyed in the range 0.4-14
mg mL-1 of iodate. The
molar absorptivity, Sandell’s sensitivity, detection limit and quantitation
limit of the method were found to be 1.71 x 104 Lmol-1 cm
–1, 1.02 x 10-2 mg
cm-2, 0.026 mg mL–1
and 0.0806 mg mL-1
respectively. The optimum reaction conditions and other analytical conditions
were evaluated. The effect of interfering ions on the determination is
described. The proposed method has been successfully applied to the
determination of the iodate in the table salt and sea water.
Key words: Iodate determination, spectrophotometry, leuco xylene cyanol FF.