Bibliography: pages 119-126. / Graphite Furnace Atomic Absorption Spectrometry (GFAAS) was used for the determination of cadmium and beryllium in coal and fly ash slurries. Sample preparation involved grinding the sample to a fine powder and slurrying it in a suitable solvent. Stable slurries were maintained by magnetic stirring during sampling. Pyrolytically coated graphite tubes were used for cadmium determinations, while beryllium was determined with platform atomisation. Ammonium dihydrogen orthophosphate and magnesium nitrate matrix modifiers were used for cadmium and beryllium determinations respectively. Calibration graphs constructed with aqueous standards containing the appropriate matrix modifier were rectilinear to at least 100 pg cadmium and 45 pg beryllium. Results were calculated with integrated peak area measurements. The detection limits were 2.9 pg for cadmium and 0.7pg for beryllium. Beryllium determinations were performed with semi-automatic sample introduction. The novel semi-automatic sampling unit utilised magnetic stirring for· the maintenance of stable slurries and operated with the standard Perkin-Elmer AS-40 autosampler. The principles of this unit were extended to the development of a fully automatic auto-sampling unit. The design and operation of both units are described. The accuracy of the methods was evaluated by analysing standard reference materials and in some cases, comparisons with acid digestion procedures. Data are presented for the analysis of South African coal and fly ash samples. The slurry methods had acceptable accuracy and precision. In comparison with the conventional acid digestion procedures using high pressure bombs, a time-saving advantage was realised.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uct/oai:localhost:11427/17285 |
| Date | January 1990 |
| Creators | Haraldsen, Lana Celeste |
| Contributors | Pougnet, M A Bruno |
| Publisher | University of Cape Town, Faculty of Science, Department of Chemistry |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Master Thesis, Masters, MSc |
| Format | application/pdf |
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