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Inductively Coupled Plasma-Atomic Emission Spectrometry/Partial Extraction Methods

Methods

• ICP-AES/Partial Extraction 10-Element Package (USGS and XRAL Laboratories) Ten trace elements were determined by ICP-AES. Sample aliquots of 1 g is treated with 5 ml HCl and 1 ml of 30% hydrogen peroxide solution to solubilize metals not tightly bound in the silicate lattice of rocks, soils, and stream sediments. An ascorbic acid-potassium iodide solution is added, and metals are extracted into a 10% 3-3-6-diisobutylketone solution as organic halides. The separated organic phase is aspirated into a multichannel ICP instrument where the concentrations of Ag, As, Au, Bi, Cd, Cu, Mo, Pb, Sb, and Zn are determined simultaneously. Since this is a partial-digestion method, those metals tightly bound in highly resistant minerals will not be extracted. See Motooka (1996) for further details. Analytical data for an experimental run are deemed acceptable if recovery for all 10 elements is ±20% on spikes at five times the limit of detection, and the calculated percent RSD of duplicate samples is no greater than 15%.

  Reporting limits for 10 elements measured by ICP-AES/Partial Extraction at USGS and USML laboratories.

  Element	Units	Lower limit	Upper limit
  Silver	ppm	0.08	400
  Arsenic	ppm	1.0	6 000
  Gold	ppm	0.10	1 500
  Bismuth	ppm	1.0	6 000
  Cadmium	ppm	0.05	500
  Copper	ppm	0.05	500
  Molybdenum	ppm	0.10	900
  Lead	ppm	1.0	6 000
  Antimony	ppm	1.0	6 000
  Zinc	ppm	0.05	500

• ICP-AES/Partial Extraction 15-Element Package (USML). This method is discussed in Folger (2000), who provides details about detection limits, although the exact differences between the methodology used by USML and that discussed above for the USGS and XRAL laboratories is not well described.  In addition to the above elements, this method adds Ga, Hg, Se, Te, and Tl.

Data analysis

		Distribution maps
Element	QA/QC	Conter- minous	Alaska	Hawai`i
Ag (ppm)	In progress			no data
As (ppm)	In progress			no data
Au (ppm)	In progress			no data
Bi (ppm)	In progress			no data
Cd (ppm)	In progress			no data
Cu (ppm)	In progress			no data
Ga (ppm)	In progress		no data	no data
Hg (ppm)	In progress		no data	no data
Mo (ppm)	In progress			no data
Pb (ppm)	In progress			no data
Sb (ppm)	In progress			no data
Se (ppm)	In progress		no data	no data
Te (ppm)	In progress		no data	no data
Tl (ppm)	In progress		no data	no data
Zn (ppm)	In progress			no data

(Return to Analytical Methods Page)

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/icp10.htm
Maintained by Jeff Grossman
Last modified: 15:03:11 Tue 06 Jan 2004
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