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X-Ray Fluorescence Major, Minor, and Trace Element Chemistry

Objectives

This task provides for high precision determinations of 10 major rock-forming elements as oxides and the determination of minor and trace elements in solid geologic materials using wavelength dispersive x-ray fluorescence (WDXRF). The accuracy achievable using the WDXRF technique for the determination of major elements as oxides is unsurpassed by any other instrumental technique. The error of determination is typically 0.5% relative error of less for major elements at crustal abundance levels. The percent relative standard deviation for trace and minor element determinations by WDXRF is typically between 5% and 10% for elements free of overlaps and concentrations of > 100 ppm. Samples are prepared at the CMERSC laboratory facility and analyzed using an EPA XRF instrument housed in their research laboratory in an adjacent building.

Planned Work

Provide wavelength dispersive XRF (WDXRF) analysis for major amd minor elements in solid geologic materials. The major element technique uses a lithium tetraborate fusion disk sample for presentation into a wavelength dispersive X-ray fluorescence spectrometer. The method is well-proven for analyzing all types of rocks, soils, and most types of minerals. The results are important in identification and chemical classification of geologic materials, as well as following temporal amd mass balance chages in geologic environments.

The minor and trace technique uses a homogeneous powdered sample which is placed in a 20 mm cuvette with an attached prolene film to prevent sample spilling. The cuvette is introduced into the spectrometer for analysis. Rocks, stream-sediments, and soils are typically analyzed to provide mineral and trace element data for petrologic, economic, and environmental studies.

The use of firm, trade, and brand names is for identification purposes only and does not constitute endorsement by the U.S. government.

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