Abstract: A sensitive and selective extraction-fluorimetric method for the determination of trace amount of dissolved aluminum in natural waters is developed in this study. Aluminum-lumogallion complex (Al-LMG) is extracted into n-hexanol, and the fluorescence can be enhanced substantially up to 20-fold. Compared to other publications in the literature, the method reported here is free from matrix effects, and the interference from iron and fluoride has been minimised successfully by Be2+ and o-phenanthroline, respectively. The detection Limit of dissolved Al is 0.25 nM, which is one order of magnitude lower than the traditional fluorescence techniques, with a precision of 5% at an Al level of 40 nM and 6.7% at an Al level of 1.0 nM in routine analyzes. The inter-calibration with electro-thermal atomic absorption spectrometry (ETAAS) technique for a variety of natural water samples shows a difference of 5-10%. The analysis of international SRM 1643C reference material by the method developed here provides a result consistent with the certified value. The successful inter-laboratory calibration practice demonstrates again the merit of present analytical procedure for the determination of Al in environmental and marine sciences.

Abstract: Polished steel samples were dissolved by electrolysis in a special cell (details given) and the solution was passed directly to a flow injection manifold as described by Krug et al. (Ibid., 1986, 179, 103). Dissolved Al was determined spectrophotometrically at 535 nm afte reduction with Eriochrome cyanine R (C. I. Mordant Blue 3) solution containing HCl, ascorbic acid and hexamine for pH adjustment. Beer's law was not obeyed and a second-derivative equation was used. The effects of electrolysis time, c.d. and electrolyte composition and flow rate were studied.