I intend to find the toxicity potential of certain metal nanoparticles on plant metabolism. Is it important to analyze the purity of the nanoparticle especially by XRD before use or not? What is the importance of this procedure?
For your studies, you should be sure that studied material is pure and, what is perhaps more important, in which phase. Nanomaterial has, in general, different structure (different phase) than its bulc version (crystal). That is why the detailled diffraction studies should be made before other studies.
Marina, the Scherrer equation should be withdrawn from scientific methods! The calculated valus depends on so many factors, that the final value can be different even on about 300%! More correct method is by Williamson and Hall - the estimation seems to be more adequate to real (correct) value of crystallite size. See my paper on this subject :-)
You can determine the structure of the your nanoparticle, Phase purity can be possible with limitations (If the impurity level is less than 2% then estimation is very difficult).
You can do XPS known as ESCA (Electron Spectroscopy for Chemical Analysis).
The preferred choice for trace metal analysis is ICP (Inductively Coupled Plasma). It is the right technique to estimate purity of your nanoparticle to parts per million level (ppm).
XRD analysis can give you the idea of crystallinity, purity and size of your synthesized metal nanoparticles.
The XRD analysis also provides info on phases. toxicity to plant cells also depend on crystalline structure and it can influence the extent of toxicity.
Apart from structure the best thing for XRD analysis is to get the crystal size and lattice distortion happens during mechanical alloying. Unless one have the idea of size reduction if difficult to optimize the mechanical alloying timing of any materials. Also what are the probable phases present, lattice parameter of the crystal are useful measurements of XRD analysis.
XRD analysis is a very important routine analysis as it gives you very fast a lot of information:
- The structure of your metal nanoparticles, you can have simultaneously mutiple structures (cubic and hexagonal in certain cases)
- Eventual secondary crystalline phases (oxides...), so the possible purity, but you will not be able to see the organic phase and then you need TGA.
- Size of your nanoparticles can be estimated using the Scherrer equation IF your nanoparticles are spherical or almost spherical
- You can also know if you have some stacking faults in your nanoparticles, as it is usually the case for cobalt metal nanoparticles.
i agree with Erwan, it is a excellent definition of possible information obtain with XRD.
In addition, after the subtraction of the XRD device contribution to line broadening (using a dedicated LaB6 microcrystalline standard powder for example), you can determine microdistortions (i.e., microstrain) in your crystallites.
its used for qualitative and quantitative analysis of a material using many softwares like xpert high score plus or others it also can be used to determined the thermal expansion a,b and c of the crystal system...
For your studies, you should be sure that studied material is pure and, what is perhaps more important, in which phase. Nanomaterial has, in general, different structure (different phase) than its bulc version (crystal). That is why the detailled diffraction studies should be made before other studies.
Marina, the Scherrer equation should be withdrawn from scientific methods! The calculated valus depends on so many factors, that the final value can be different even on about 300%! More correct method is by Williamson and Hall - the estimation seems to be more adequate to real (correct) value of crystallite size. See my paper on this subject :-)
@Powel, thank you for your contribution.Could you please provide the paper you mentioned
I would like to add to this discussion and ask some questions.
Can I apply XRD to milling of metal oxides? For example, if I run XRD on 1 g of bulk powder, and I want to compare it to milled metal oxide, must this milled material also be 1 g?
Thank you.
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