Simultaneous flow-injection determination of aluminium and zinc using LED photometric detection

A flow photometer with a multi-LED detector was applied to the simultaneous determination of aluminium and zinc with microcomputer control of photometric measurements and data processing. Xylenol Orange is the photometric reagent and the reaction is carried out in acetate buffer. Calibration graphs are linear for both metals in the concentration ranges 0.2–25 μg ml^?1 (Al) and 0.2–30 μg ml^?1 (Zn). Both elements can be determined for Al to Zn ratios varying from 0.01 to 100 with r.s.d. 1.1 and 1.4%, respectively. The method developed was applied to the determination of Al and Zn in alloys.