Spectrophotometric Determination of Iron(II) by Extraction of Its Ion-Associated Complex with 3-(2-Pyridyl)-5, 6-diphenyl-1, 2, 4- triazine and Tetraphenylborate Anion into Molten Naphthalene

A spectrophotometric method has been developed for the determination of iron(II) via extraction of its ion- associated complex with 3-(2-pyridyl)-5, 6-diphenyl-1, 2, 4-triazine and tetraphenylborate anion into molten naphthalene. The optimum pH range for extraction of the complex is 1.9-5.9. The solid naphthalene containing the ion-associated complex is separated by filtration and dissolved in acetonitrile. Beer′s law is obeyed in the concentration range 2.0-23.8μg of iron in 10cm3 of acetonitrile solution. The molar absorptivity and Sandell′s sensitivity are 2.54×104l mol-1 cm-1 and 0.0022μg cm-2 at 553nm, respectively. Ten replicate analyses of a sample containing 11.9μg of iron give a mean absorbance of 0.542 with the relative standard deviation of 0.54%. The interference of various ions has been studied. The present method has been successfully applied to the determination of iron in standard alloy samples and metallic aluminum powder.