Micellar Aided Chromogenic Reagents for Simultaneous Spectrophotometric Determination of Aluminium and Iron

Simple and novel spectrophotometric method is described for simultaneous determination of aluminium and iron. The method is based on the metal ions complexes formed by aluminium and iron with mixed chromogenic reagents of 1, 10 phenanthroline and 8-hydroxyquinoline (oxine). The derivatives have absorption maxima at 400 nm and 510 nm respectively in the presence of cetyltrimethyl ammonium bromide (CTAB) as micellar media (surfactant) maintained at pH 5. Reaction conditions were optimized and the linear dynamic ranges for determination of aluminum and iron were found be 0.8 – 12.0 μg/mL and 0.6 – 8.0 μg/mL respectively. The standard deviation (S.D) and coefficient of variation (CV) for the simultaneous determination was 0.018 and 0.45% for aluminium and 0.03 and 1.5% for iron (II). The recoveries were between 102 % and 106 %, 101.2 % and 104 % for aluminium and iron respectively at 95 % confidence level (p≥0.05). The proposed method was successfully applied to the assay of aluminium and iron in rock minerals, lubricating oil and water samples. The results and paired t-test for the analyzed samples were found to be in satisfactory agreement (shows no significant difference) with those acquired by the flame atomic absorption spectrophotometric (FAAS) technique.