AUTOMATED MEASUREMENT OF AQUEOUS ALUMINUM BY THE PYROCATECHOL VIOLET METHOD

In response to our need for a rapid method of analyzing numerous alumi nium samples, we developed an automated procedure for measuring total monomeric aluminum in aqueous samples. Two separate designs for a cont inuous microflow analyzer are presented which enable detection over a combined range of 20 mug Al/l to 1 000 mug Al/l. The best fit to the c alibration curve for the high sensitivity manifold is not linear (r2 = 0.998) as previously reported but third order (cubic, r2 = 1.000). Th e choice of equations for curve fit for the low sensitivity range is l ess critical as first and third order equations provide comparable fit . Between-sample contamination is less that 3% and reproducibility is high; less than 1% variation for high (200 - 1000 mug Al/l) concentrat ions and less than 7% for lower (20 - 300 mug Al/l concentrations. Ana lysis of both water and soil extract samples for aluminum should be fa cilitated by use of this system.