Spectrophotometric determination of iron(III) in ore, pharmaceutical formulations, plant material and foodstuff using piroxicam

Abstract

Piroxicam (PR) has been proposed as a sensitive and selective reagent for the spectrophotometric determination of Fe(III) in ore, pharmaceutical formulations, plant material and foodstuff. The method is based on the formation of a chloroform-soluble red

coloured 1:1 complex by the reaction of Fe(III) with PR in Walpole buffer. Beer's law is valid over the concentration range of 0.4-6.4 ppm. The coloured complex exhibits an absorption maximum at 510 nm with molar absorptivity of 1.82×10⁴ l mol^-1 cm^-1 and Sandell's sensitivity of 17.32 ng cm^-2. The absorbances are found to increase linearly with increase in concentration of iron, which are corroborated by the calculated correlation coefficient value (0.9992). The effects of foreign ions in the determination of Fe(III) have been studied. Statistical comparison of the results with those of direct AAS method shows good agreement and indicates no significant difference in precision.