DETERMINATION OF SELENIUM IN MUNICIPAL-WA STE INCINERATION FLY-ASH BYMICROWAVE DIGESTION GRAPHITE-FURNACE AAS WITH A ZEEMAN-EFFECT BACKGROUND CORRECTION

Municipal-waste incineration fly-ash samples were digested by microwav e-digestion procedures with an acid mixture of HClO4-HNO3-HF. Then, se lenium in the digested sample solution (in 1 M-HCl, trace-HClO4) was d irectly determined using graphite-furnace AAS with a Zeeman-effect bac kground correction. Platform atomization was used and peak-area absorb ance measurements were utilized. Palladium and nickel were used as mod ifiers. The palladium modifier stabilized selenium at a higher tempera ture than did the nickel modifier, resulting in a better sensitivity. An aqueous calibration curve was used and the method of additions was not necessary. The present investigated method was applied to the anal ysis of a certified reference material (BCR No. 176). The analytic res ult was in good agreement with the certified value. The present method has been successfully applied to the analysis of actual samples.