DETERMINATION OF ALUMINUM IONS BY INDIRECT POTENTIOMETRY IN A FLOW SYSTEM

A potentiometric system is described for the indirect flow determinati on of Al3+ with an aluminum wire as indicator electrode. The method is based on the reaction bem een aluminum and fluoride ions at pH 5.0 in acetate buffer. The reduction in activity of fluoride ions is detecte d by the aluminum electrode. The response was optimized for the flow r ate of solution, length of reaction tubing, concentration of fluoride reagent, and pH of the buffer. The response was linear with concentrat ion of aluminum in the range of 0.5 to 50 ppm with a relative standard deviation (RSD) of 0.7%. There was negligible interference from a ran ge of cations and anions when their concentrations were less than 20 p pm.