Contact

Joachim Krause
Department of Analytics

Phone: +49 351 260 - 4420

Electron Probe Micro Analysis (EPMA)

The EPMA is an analytical technique used to non-destructively determine the chemical composition of small volumes of solid materials. The associated instrument, the electron probe micro analyzer, is informally referred to as an electron microprobe.

Technical Specifications

EPMA - JEOL JXA-8530F HyperProbe
Imaging modes: secondary-electron imaging (SEI), back-scattered electron imaging (BSE), and cathodoluminescence imaging (CL)
Energy-dispersive spectrometry (EDS)
Five crystal spectrometers for Wavelength-Dispersive Spectrometry (WDS)
2D element mapping possible
Non-destructive
High resolution up to 500 nm

Application

Chemical spatially resolved analysis of individual mineral phases
Most commonly used method for chemical mapping of geological materials at small scales

Electron Probe Micro Analysis, (EPMA) ©Copyright: Schulz, Tina — Set-up of the electron probe micro analyzer, Photo: HZDR

Sample Requirements

Polished thin sections or polished embedded grain mounts
Sample areas down to 0.5 µm, depending on analytical conditions

Limitations

The light elements H - Li are not detectable
Some elements generate specific X-rays with overlapping peak positions; these have to be de-convoluted
Cannot distinguish between the different valence states of Fe and other elements; the ferric/ferrous ratio must be determined by other techniques

Selected Publications ►

Atanasova, P.; Krause, J.; Moeckel, R.; Osbahr, I.; Gutzmer, J.;
"Trace element geochemistry of sphalerite in contrasting hydrothermal fluid systems of the Freiberg district, Germany: insights from LA-ICP-MS analysis, near-infrared light microthermometry of sphalerite-hosted fluid inclusions, and sulfur isotope geochemistry", Mineralium Deposita 54(2019)2, 237-262
DOI-Link: 10.1007/s00126-018-0850-0

Burisch, M.; Hartmann, A.; Bach, W.; Krolop, P.; Gutzmer, J.;
"Genesis of hydrothermal silver-antimony-sulfide veins of the Braunsdorf sector as part of the classic Freiberg silver mining district, Germany", Mineralium Deposita 54(2019)2, 263-280
DOI-Link: 10.1007/s00126-018-0842-0

Kern, M.; Möckel, R.; Krause, J.; Teichmann, J.; Gutzmer, J.;
"Calculating the deportment of a fine-grained and compositionally complex Sn skarn with a modified approach for automated mineralogy", Minerals Engineering 116(2018), 213-225
DOI-Link: 10.1016/j.mineng.2017.06.006

Bachmann, K.; Osbahr, I.; Tolosana-Delgado, R.; Chetty, D.; Gutzmer, J.;
"Major and Trace Element Geochemistry of the European Kupferschiefer – An Evaluation of Analytical Techniques", Geostandards and Geoanalytical Research (2018)
DOI-Link: 10.3749/canmin.1700094

Bauer, M. E.; Burisch, M.; Ostendorf, J.; Krause, J.; Frenzel, M.; Seifert, T.; Gutzmer, J.;
"Indium and selenium distribution in the Neves-Corvo deposit, Iberian Pyrite Belt, Portugal", Mineralogical Magazine 82(2018), S5-S41
DOI-Link: 10.1007/s00126-018-0850-0

How does it work? ►

EPMA works similarly to a scanning electron microscope, with the added capability of chemical analysis: The sample is bombarded with electron beams and emits a characteristic X-ray radiation which is detected by crystal spectrometers. The respective element concentrations can be determined by comparison measurements of a standard material of known composition and subsequent extensive correction calculations.