Full text
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| Author(s): |
Margareth Sugano Navarro
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Geociências (IG/BT) |
| Defense date: | 2004-06-15 |
| Examining board members: |
Horstpeter Herberto Gustavo Jose Ulbrich;
Jacinta Enzweiler;
Antonio Jose Ranalli Nardy
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| Advisor: | Horstpeter Herberto Gustavo Jose Ulbrich |
| Abstract | |
The steps for the development of the analytical routines leading to the determination of the rare earth elements (REE) with the use of ICP-AES and ICP-MS techniques are discussed in this contribution. The set-up of these routines was also evaluated with determinations of REE in several granitoid rocks from the Piedade-Ibiuna (SP) and Cunhaporanga (PR) complexes, and the results compared with those obtained in other laboratories (University of Kansas, Lawrence) with ICP-MS and INAA. The work previously performed for the adaptation of REE determination with ICPAES was reviewed, allowing analyses to be realized with better results for concentrations close to 10 times the chondrite value. At lower concentrations, REE analysis have to be performed with ICP-MS. The ICP-MS technique shows much better accuracy and precision than ICPAES, but presents problems of its own. Instrumental drift corrections, as well as corrections due to molecular interferences, are mandatory. Evaluation of the successfully adapted routines was realized analyzing international reference materials several times and applying statistical tests. A comparison of results with three dissolution techniques (acid attack in microwave oven, use of Parr type bombs, and alkaline fusion with borates) showed that both acid attack and alkaline fusion with later chromatographic separation are rather efficient alternatives for the determination of REE, although Zr and Hf are not fully recovered in many acid igneous and equivalent gneissic rocks. (AU) | |