I'm currently searching for the optimal characterization technique to determine the elemental composition of my Ir-Au nanoparticles. I have EDS, XPS, and ICP-OES data, however I'm skeptical on the results as they are all dependent on the homogeneity of the synthesized sample taken to be tested. In my searching I found XRF and AAS to be possible candidates. Any commend or insight would be appreciated!!
i think EDS, cause its scanning beam goes to deeper spots in the sample
John Jherson Bofill
In what form are your PGM nanoparticles - colloidal suspension, on a support, or pure powder? How much do you want to use/risk as a sample? There are minimum mass considerations related to the standard error you wish to achieve in the measurement. All metrology is dependent on a representative sample being taken. We must talk about sample heterogeneity rather than sample homogeneity. The good news is that basic sampling is amenable to fairly simple math as expounded in the works of Pierre Gy. See this webinar (free registration required):
Keys for Successful Analysis – Representative Sampling & Estimation of Standard Error Calculation
https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W190613KeysLD
The above deals with the minimum mass issues.
You can dissolve in appropriate acid mixes an appropriate amount of sample for AAS or ICP. XRF has a wide range from ppm to % and takes a reasonable amount of sample. Techniques that are electron microscopy based take small scans of the sample. Indeed, in the whole history of electron microscopy no more than a few hundred grams of material have been imaged. XPS is very useful as it tells you about the surface of the material - vital in applications such as catalysis. In a mixed system such as yours, the surface composition MUST be different from the bulk composition due to processes such as chemisorption induced segregation. Again, another free webinar (now a little dated):
Nanotechnology characterization techniques
https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W140327-nanotechnology-characterization-techniques
It depends on your work. If you want to know the composition of elements present in your material. EDX is the most famous tool for that. Doing ICP-OES for solid fractions Is quite challenging.
As I said, it depends on your purpose, like what objective you want to achieve analysis depends on that.
Try XRF if it is powdered sample.
Find some more relevant elemental analysis techniques from these papers
https://pubs.rsc.org/en/content/articlehtml/2018/nr/c8nr02278j
https://pubs.rsc.org/en/content/articlehtml/2023/nr/d2nr07163k
https://pubs.rsc.org/en/content/articlelanding/2021/ma/d1ma00538c