X-ray Fluorescence Spectrometry

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XRF

Analysis at USGS Laboratories of Major Elements by Wavelength-Dispersive X-ray Fluorescence Spectrometry

Method

Sample aliquants of 800 mg are ignited at 925°C for 45 minutes, and loss on ignition (LOI) is determined gravimetrically. Samples are then fused with lithium tetraborate at 1120°C. The resultant molten material is poured into a mold, yielding a homogeneous, optically flat glass disc for presentation to the x-ray spectrometer. Major elements (Na₂O, MgO, Al₂O₃, SiO₂, P₂O₅, K₂O, CaO, TiO₂, MnO, and total Fe calculated as Fe₂O₃) are determined on the samples using wavelength dispersive x-ray fluorescence spectrometry using the method of Taggart and others (1981, 1987), Mee and others (1996), and Taggart and Siems (2002). Concentrations are determined using previously prepared calibration curves derived from a variety of international reference materials.

Reporting limits for major elements measured by XRF.

Element Units Lower limit Upper limit

SiO₂ wt% 0.10 99.0

Al₂O₃ wt% 0.10 58.0

Fe₂O₃ wt% 0.04 28.0

MgO wt% 0.10 60.0

CaO wt% 0.02 60.0

Na₂O wt% 0.15 30.0

K₂O wt% 0.02 30.0

TiO₂ wt% 0.02 10.0

P₂O₅ wt% 0.05 50.0

MnO wt% 0.01 15.0

LOI wt% 0.01 100.0

Data analysis

		Distribution maps
Element	QA/QC	Conter- minous	Alaska	Hawai`i
SiO₂ (wt%)	In progress		no data	no data
Al₂O₃ (wt%)	In progress		no data	no data
Fe₂O₃ (wt%)	In progress		no data	no data
MgO (wt%)	In progress		no data	no data
CaO (wt%)	In progress		no data	no data
Na₂O (wt%)	In progress		no data	no data
K₂O (wt%)	In progress		no data	no data
TiO₂ (wt%)	In progress		no data	no data
P₂O₅ (wt%)	In progress		no data	no data
MnO (wt%)	In progress		no data	no data
LOI (wt%)	In progress		no data	no data

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U.S. Department of the Interior, U.S. Geological Survey
This page is part of U.S. Geological Survey Open-File Report 2004-1001
URL: http://www-tin.er.usgs.gov/geochem/doc/xrf.htm
Maintained by Jeff Grossman
Last modified: 15:03:10 Tue 06 Jan 2004
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Element	Units	Lower limit	Upper limit
SiO₂	wt%	0.10	99.0
Al₂O₃	wt%	0.10	58.0
Fe₂O₃	wt%	0.04	28.0
MgO	wt%	0.10	60.0
CaO	wt%	0.02	60.0
Na₂O	wt%	0.15	30.0
K₂O	wt%	0.02	30.0
TiO₂	wt%	0.02	10.0
P₂O₅	wt%	0.05	50.0
MnO	wt%	0.01	15.0
LOI	wt%	0.01	100.0