Facile and Sensitive Spectrophotometric Method for the Determination of Vanadium

Abstract

Highly sensitive and simple spectrophotometric method is described for the determination of
vanadium(V) using a new reagent Azure B. The method is based on the reaction of vanadium(V) with
potassium iodide in an acidic condition to liberate iodine, the liberated iodine bleaches the blue color
of Azure B and is measured at 636 nm. The decrease in absorbance is directly proportional to
vanadium concentration. The method obeys Beer’s law over a concentration range of 0.02–9.0
μg mL-1 vanadium. The molar absorptivity, Sandell’s sensitivity, detection limit and quantification
limit of the reaction system were found to be 4.33 × 104
L mol−1
cm-1, 0.0011 µg cm−2
, 0.75 µg mL−1
and 2.27 µg mL−1
respectively. The optimum reaction conditions and other analytical parameters have
been evaluated. The proposed procedure has been successfully applied to the determination of
vanadium in water, soil, plant material, urine, pharmaceutical preparations and steel samples. The
results were compared to those obtained with the reference method.