Kinetic Spectrophotometric Determination of Trace Aluminum by Catalytic Activity of Al 3+ on the Oxidation of Methylene Blue by Hydrogen Peroxide

Abstract

A novel kinetic spectrophotometry for the determination of trace aluminum is described based on the catalytic activity of Al3+ on the redox reaction between methylene blue (MB) and hydrogen peroxide in acetate buffer (pH 3.8). The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dye at the maximum absorption wavelength of 670 nm. The variables that affected the reaction rate were fully investigated, and the optimum conditions were established. Aluminum can be determined in the range of 0–80 ng mL−1 with a detection limit of 1.0 ng mL−1. The relative standard deviation for 10 replicate determinations of 40 ng mL−1 aluminum is 0.9%. The method was used to determine aluminum in tap water and biological samples and produced satisfactory results.