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.