Abstract
The spectrophotometric method for the determination of Fe (III) and Al (III) by using ο-hydroxyhydroquinonephthalein (HyPh) was devised and those metals in the presence of each other were also determined. To the solution containing less than 3.3μg of Fe (III), 3.0 ml of phosphate buffer (pH 8.8) and 1.0 ml of 5.0×10-4M HyPh methanol solution were added and the whole volume was made up to 10 ml with distilled water. The solution was kept at 60°C for 30 minutes and then cooled for 15 minutes and then, the absorbance of it was measured at 605 nm or 620 nm taking the distilled water as the reference. Determination of Al(III) was carried out in the same manner as above with a slight modification that the reaction mixture was left to stand at (2025)°C for 20 minutes and the absorbance was measured at 530 nm against the reagent blank. The concentration of Fe (III) in the presence of Al (III) was determined by using the absorbance at 620 nm against distilled water. The calibration curves were linear in the range of 0 to 3.3 μg/ 10 ml of Fe (III) and 0 to 3.2 μg/10ml of Al(III). According to the Sandell's expression, the sensitivities were 0.0003 μg/cm2(605nm), 0.0004 μg/cm2(620nm)of Fe(III)and 0.0002μg/cm2 (530nm)of Al(III) for an absorbance of 0.001, respectively.
