Abstract

B. K. Puri¹* S. Abdul Wasi² and Mohan Katyal¹

A sensitive and selective spectrophotometric method has been developed for the determination of iron as Fe (II) and Fe (III) using 9, 10-phenanthrenequinone monoxime (PQM) as the complexing agent. Fe (II) and Fe (III) react with PQM to form coloured water insoluble complexes which can be adsorbed on microcrystalline naphthalene in the pH ranges 3.7-6.2 and 2.0-8.4 respectively. The solid mass consisting of the metal complex and naphthalene is dissolved in DMF and the metal determined spectrophotometrically by measuring the absorbances Fe (II) at 745 nm and Fe(III) at 425 nm. Beer's law is obeyed over the concentration range 0.5-21.0 g if iron (II) and 21.0-168.0 g of Fe(III) in 10ml of DMF solution. The molar absorptivities are 1.333 x 10-4 1.mole-1cm-1 for Fe (II) and 2.428 x 103 1.mole-1cm-1 for Fe (III).. Ten replicate determinations of sample solutions containing 10.5 g of Fe (II) or 98.0 g of Fe (II) gave mean absorbances of 0.250 and 0.425 with relative standard deviation of 0.95 and 0.88 % respectively. The interferance of various ions has been studied and the method has been employed for the determination of iron in various standard reference alloys, beers, wines,ferry gluconate, human hair and environmental samples.

Determine; Microcrystalline; Naphthalene

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