Abstract: A double hydride generation technique was developed and successfully used for the determination of total ultratrace amounts of selenium by atomic fluorescence spectrometry (AFS). In this technique, the acid digested sample solution was used for the generation of selenium hydride first, after which, the SeH2 formed was reacted with, and absorbed in, a small volume of alkaline solution (0.5 mol L-1 NaOH+0.05 mol L-1 H2O2), in which automated organic selenium digestion by the flow injection technique was pursued. The alkaline solution with the selenium absorbed was mixed with the reductant and then acidified to achieve hydride generation for the second time. The concentration factor depends on the volume ratio of the sample and the alkaline solution. Selenium hydride was atomized in a quartz atomizer with a mini-hydrogen diffusion flame and detected by AFS. Under the conditions employed, a detection limit of 2-6 pg Se mL-1 and 2.8% relative standard deviation (RSD) (with 1 ng mL-1 Se, n=11), and 12% RSD (with 0.05 ng mL-1 Se, n=7) were obtained by this enrichment technique and AFS detection.

Abstract: The method previously described (Ibid., 1991, 243, 65) for flow injection electrolytic dissolution - ICP-AES was applied to multi-element analysis of aluminum alloys. The electrolyte used was 1 M HNO3 and electrolysis was carried out at 1150 mA cm-2 for 20 s. For determination of Zn, Si, Fe, Mn, Cr, Mg and Cu, coefficient of variation were 1 to 6.5%. Up to 500 µg mL-1 of Al did not interfere in the determination of 1 µg mL-1 of the above elements. Results agreed well with certified values for standard samples.