I have a nanomaterial that contains gold, silver and chloride and I want to do EDS to quantify their relative content. I need something to determine the k factor between these three elements. I'm wondering what do people usually do to determine the k factors? Here quantification of chloride is not required. My sample is ~2 nm in dimension,and it's difficult to prepare standard sample close to that dimension for EDS quantification. Any other suggestions?
Thanks!
I think you need standard sample which the quantity is known. Then, comparison between the standard sample and your sample gives the quantity of the element in your sample.
About sample :
the best is to make standarts of the same morphology than your samples to be quantified. Don't forget that the volume of analysis (few µm3=f(E,Z)) is much larger than your electronic resolution even if Au and Ag are heavy Z. Think about penetration depth of the beam vs thickness of your sample, signal may be weak compared to support. Using a serie of known sample of various Au/Ag ratios as standarts and perform a quantify/match could be ok too.
About technique:
WDS would be more accurate if you have acces to machine or EDS in a TEM (to avoid support signal)
best,
You can use both EDS and PIXE, as they see well Au, Ag and Cl. A thin layer approach would be better because you will eliminate the matrix effects' problem. The range of electrons would be of a few microns or tenths of microns, and the range of protons would be of microns or tens of microns, depending on energy. So you should prepare a thin layer of nanoparticles below some tenths of microns. Perhaps some corrections for rough surface may be necessary, and there are articles and programs for that both in EDS-SEM or EDS-TEM and PIXE.
If you cannot prepare a thin layer of nanoparticles, you will have matrix effects, but they are accounted for by various codes, e.g. GUPIX for PIXE. See also my book https://www.researchgate.net/publication/256426906_Eugen_A._Preoteasa_Elena_Preoteasa_and_Ioana_Suciu.._ATOMIC_AND_NUCLEAR_SURFACE_ANALYSIS_METHODS_A_NOVEL_PERSPECTIVE_FOR_THE_CHARACTERIZATION_OF_DENTAL_COMPOSITES_Nova_Science_Publishers_Inc._NY_2012__ISBN_978-1-61470-208-5._www.novapublishers.com_220_p._(xiv__206)?ev=prf_pub
and references therein.
Book Eugen A. Preoteasa, Elena Preoteasa and Ioana Suciu.. ATOMIC...
Have you tried the Zeta factor method to quantify the spectra? You still need a reference, but the advantage over k-factor or Cliff Lorimer method is that you can correct for absorption effects. See the literature below to give you a reference for the method.
M Watanabe and DB Williams, Journal of Microscopy 221 (2006) p. 89
Bert
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