A Semi-Automated Colorimetric Method for the Determination of Monomeric Aluminum Species in Natural Waters by Flow Injection Analysis

Abstract

Abstract A two-channel flow injection analysis method is presented for the fractionation and determination of monomeric aluminum species in natural waters. The method is based upon the colorimetric reaction of monomeric aluminum with pyrocatechol violet at pH 6.1. The first channel measures total monomeric aluminum, while the second determines the non-exchangeable fraction. The method was found to be linear up to 1.0 mg Al/L with a lower limit of detection of 7.0 μ Al/L. The effects of iron, fluoride and several organic ligands were investigated. The analytical performance of the method was assessed in both the laboratory and as part of a large aquatic chemistry survey. The method was compared with the 8-hydroxyquinoline complexation method for determining monomeric aluminum using 329 natural and quality control samples.