Flow Injection Analysis for Trace Aluminum with On-Line Preconcentration and Spectrophotometric Detection

Abstract

We developed a flow injection analysis method for the determination of trace aluminum in water coupled with on-line preconcentration on salicylideneamino-2-thiophenol immobilized glass beads (SAB) and spectrophotometric detection using Pyrocatechol Violet (PV). The FIA system consisted of two pumps, a 6-port switching valve, a concentrator column, a UV/VIS spectrophotometric detector and a recorder. A sample solution was combined with a succinic acid/NaOH buffer (pH 6.0) and hydroxylammonium chloride and this mixture was loaded on the concentrator column. Aluminum retained on the concentrator column was eluted with 0.1 mol dm⁻³ nitric acid and mixed with PV. A colored PV-aluminum complex was spectrophotometrically monitored at 576 nm. A linear relationship was observed between the peak height and aluminum concentration at a constant sample volume. A correlation coefficient of 0.9997 and determination limit of 3.7 nmol dm⁻³ were obtained for a sample volume of 10 ml. Relative standard deviations were below 2% at nmol levels. Aluminum traces in some Kanazawa City tap water samples were determined by this method.