Application of portable XRF to the direct analysis of till samples from various deposit types in Canada
| Autor: | Lilianne Pagé, M. Beth McClenaghan, Gwendy E.M. Hall |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Detection limit
Laboratory methods Chemistry Analytical chemistry chemistry.chemical_element Mineralogy General Chemistry 010501 environmental sciences 010502 geochemistry & geophysics 01 natural sciences Mercury (element) chemistry.chemical_compound Geochemistry and Petrology General Earth and Planetary Sciences Aqua regia Direct analysis 0105 earth and related environmental sciences General Environmental Science |
| Zdroj: | Geochemistry: Exploration, Environment, Analysis. 16:62-84 |
| ISSN: | 2041-4943 1467-7873 |
| Popis: | In this study, results by direct portable XRF (‘pXRF’) on unsieved till samples were compared with those by established laboratory methods (aqua regia or fusion ICP-MS and ICP-ES) on the In general, the performance of pXRF in the four test areas was very good where concentrations of elements of interest (indicator or pathfinder elements) were substantially above detection limits by this technique (in the low ppm range for many elements). The following elements, shown to be useful indicator elements (important constituents of the ore/commodity) or pathfinder elements (those associated with the commodity elements) by the established methodology, showed similar patterns by pXRF on the unsieved material: Zn, Cu, Pb, and As at Halfmile Lake; W, Mo, Cu, Zn, Pb, and As at the Sisson deposit; Zn, Pb, and Fe at Pine Point; and Ca, Sr, Cr, and Ni at Triple B. Pathfinder elements whose concentrations were too low for determination by pXRF include: Ag and Sb at Halfmile Lake; Ag and Cd at Sisson; Cd, S, and Se at Pine Point; and Co, Mg, P, U, and Th at Triple B. The high background for Bi by pXRF, equivalent to c . 50 ppm, and its noisy signal precluded its use at Halfmile Lake and Sisson. Elements which tended to show poor precision (three analyses each sample) by pXRF in some samples due to sample heterogeneity include Sn, V, and W. Mercury was erroneously reported for the majority of samples in the low ppm range by pXRF whereas its concentration in fact was in the low ppb range. Several Pb-, Zn- ( c . 1% Pb, Zn) and Fe-rich (up to 16% Fe) samples demonstrated spectral interferences by: Pb on As, Th and Se; Zn on Cu; and Fe on Co. Results for six till samples analysed in Ziploc® and Whirl-Pak® bags showed that Ziploc® absorbs fewer low-energy photons and hence is preferable for determining light elements such as Si, K and Ca. Supplementary material: Four data-sets are available at http://www.geolsoc.org.uk/SUP18897 |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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