Chromatographic pre-concentration of iron(III) with 1,10-phenanthroline and tetraphenylborate supported on naphthalene

Abstract

A method has been established for the determination of trace amounts of iron employing chromatographic pre-concentration of iron(II) with 1,10-phenanthroline and tetraphenylborate supported on naphthalene. The optimum pH range for the adsorption is 3.2–6.2. Naphthalene containing iron(II) complexes is dissolved in acetonitrile and the absorbance is measured at 508 nm. Beer's law is obeyed over the concentration range 2.0–32.0 µg of iron in 10 ml of acetonitrile solution. The molar absorptivity was calculated to be 1.13 × 10⁴ l mol^–1 cm^–1 at 508 nm. Seven replicate analyses of a sample solution containing 16.0 µg of iron gave a mean absorbance of 0.325 with a relative standard deviation of 0.31%. The method has been successfully applied to the determination of iron in aluminium alloy and powder and sea water samples.