Glow discharge spectroscopy

from Wikipedia, the free encyclopedia
GDOS at the University of Ravensburg-Weingarten 2015
Principle: Rowland Circle

Glow Discharge ( English Glow Discharge Optical Emission Spectroscopy , GDOS / GDOES ) refers to a spectroscopic method for the quantitative analysis of metals and also other nonmetallic solids. The process goes back to Grimm.

In contrast to spark spectrometry , GDOES can also analyze layer structures. The GDOES can be used for the quantitative and qualitative determination of elements and is therefore a sub-area of analytical chemistry .

The metallic samples are used as cathodes in a DC voltage plasma . Starting from the surface, the sample is gradually removed in layers by cathode sputtering with argon ions. The removed atoms enter the plasma by diffusion . Stimulated by impact processes, these photons emit with characteristic wavelengths, which are recorded by means of a downstream spectrometer and then quantified.

If a high-frequency alternating voltage is used to generate the plasma and the glow discharge source is constructed accordingly, non-metallic samples can also be examined.

Different sensors are used as sensors. PMTs ( photomultiplier ) can detect the smallest traces and also high concentrations of the sensor-specific element. A complete spectrum of elements can be measured with the appropriate layer thickness using a CCD ( charge-coupled device ).

application

Glow discharge spectroscopy is an established method for characterizing steels and paints . More recent developments relate to the analysis of porous electrodes from lithium-ion accumulators .

literature

  • R.Kenneth Marcus, José Broekaert: Glow Discharge Plasmas in Analytical Spectroscopy Wiley, ISBN 0-471-60699-5 .
  • Thomas Nelis, Richard Payling: Glow Discharge Optical Emission Spectroscopy - A Practical Guide .

Web links

Individual evidence

  1. ^ W. Grimm: A new glow discharge lamp for optical emission spectral analysis In: Spectrochimica Acta Part B: Atomic Spectroscopy Volume 23, 1968, pp. 443-454, doi: 10.1016 / 0584-8547 (68) 80023-0
  2. ↑ H. Takahara, M. Shikano, H. Kobayashi: Quantification of lithium in LIB electrodes with glow discharge optical emission spectroscopy (GD-OES) In: Journal of Power Sources . Volume 244, 2013, pp. 252-258, doi: 10.1016 / j.jpowsour.2013.01.109
  3. ↑ N. Ghanbari, T. Waldmann, M. Kasper, P. Axmann, M. Wohlfahrt-Mehrens: Detection of Li Deposition by Glow Discharge Optical Emission Spectroscopy in Post-Mortem Analysis In: ECS Electrochemistry Letters 4, 2015, p. A100 -A102, doi: 10.1149 / 2.0041509eel