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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Assessment of Dissolution of Silicate Rock Reference Materials with Ammonium Bifluoride and Nitric Acid in a Microwave Oven

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Author(s):
Magaldi, Thais T. [1] ; Navarro, Margareth S. [1] ; Enzweiler, Jacinta [1]
Total Authors: 3
Affiliation:
[1] Univ Campinas UNICAMP, Inst Geosci, Rua Carlos Gomes 250, BR-13108855 Campinas, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: GEOSTANDARDS AND GEOANALYTICAL RESEARCH; v. 43, n. 1, p. 189-208, MAR 2019.
Web of Science Citations: 4
Abstract

The complete dissolution of representative test portions of powdered rock samples for the determination of the mass fractions of trace elements by ICP-MS relies either on aggressive and time-consuming acid digestions or fusion/sintering with appropriate fluxes. Here, we evaluate a microwave oven dissolution method that employs a solution of NH4HF2 and HNO3. The entire procedure occurs in a closed vessel system and takes up to 4 h. In hundreds of digestions, the precipitation of fluorides was never observed. Replicate decomposition of 100 mg of twenty-one international reference materials (RMs) of igneous rocks, and also one of a shale presented mostly satisfactory recoveries of forty-one trace elements. Important exceptions were Zr and Hf in G-2 and GSP-2 (mean recoveries of ca. 70%), although for four other felsic rock RMs, the digestion was complete. For ultramafic rock RMs, we present Cr results that indicate quantitative dissolution of Cr-bearing phases. We discuss the findings and conclude that advances in sample preparation of geological materials for instrumental analysis would benefit from a better understanding of how specific characteristics, such as composition and crystallinity of certain minerals, may affect their reactivity. (AU)

FAPESP's process: 18/07317-3 - 10th International Conference on the Analysis of Geological and Environmental Materials
Grantee:Jacinta Enzweiler
Support Opportunities: Research Grants - Meeting - Abroad