I have received my results for synthesized Fe-NPs (green synthesis) FESEM+EDS from the laboratory. However, I am facing trouble interpreting the result. It came with 19 images for FESEM and 3 charts for EDS.
Please I need help regarding the interpretation.
Thanks
Dear Mahadi Danjuma Sani , probably the best recommendation for your issues would be to contact with the FESEM-EDS staff and asking them all your doubts. Probably you are paying for these data and so some explanation or help should come from them. In some facilities, however, data adquisition and interpretation have separate cost and in this case you have to pay to get a proper data interpretation (depending on the case of data, interpretation can easily cost more than the data adquisition).
Often when you are studying your samples by FESEM-EDS you want to know morphology (size, size distribution, shape, etc) and chemical composition of your samples.
In your case a green synthesis was carried out to obtain Fe-NPs, so the FESEM images would help you to see if such NP´s were formed or not. If they were formed you can study their size dispersity (may be some are 100nm in diameter and some show just 5nm diameter or may be you have a range of sizes between these two... or all of them show the same size.
Images can show you also if the NP´s are clean or still some dirt or residues of the synthesis are contaminating your NP´s.
May be you spected round NP´s, but you got something different, like nanotriangles or cubes or flat flackes... images would show you this too.
Once you know what your sample looks like you want to know what these NP´s are composed. Here EDX come to help. EDX provides you with a elemental composition of your sample, so it shows you what elements are present in your sample... well in the area of your sample that is analyzed. EDX can be performed on a point of your sample or on a surface of your sample.
FESEM images of the regions or points where the microscopists took the EDS could be included among your set of images. This is relevant, specially when your sample shows diversity of objects, (NP´s, NP´s of different type, shape etc, amorphous material, etc) or even when your sample is quite homogeneous, it is interesting to know if it is also homogeneous in its composition.
So, if your 3 EDS charts are different it means you have different compositions on different areas or points of your sample. Imagine one of your EDS spectra shows a high content of Fe... well probably it is one of your NP´s .
Now, imagine that another EDS spectrum shows large bands for C, may be it is some residue from your green reactants... it could also shows some O (from functional groups rich in O).
If all your three spectra are the same it probably means that the microscopists took data in several points of your sample and all of them showed the same composition.
Imagine that your EDS shows high Fe bands, and also important C bands, or O bands, well in this case you should think about an interpretation for such a spectrum. It could be that your Fe NP´s are actually iron oxide NP´s or that they are coated with a shell of some organic material rich in C? .
EDS gives you information about the "superficial" composition of your sample, I mean, you excite your sample with the e-beam, and it releases X-rays. The e-beam only reaches a superficial part of the sample and therefore it only gives you info about this area. When you are dealing with NP´s you don´t need to worry about it.
EDS gives you info about elements of your sample, but depending on the EDS detector installed in the microscope some elements are detectable and other do not. Often heavy elements are easily detectable but lighter ones are not. New , sensitive detectors can identify lighter elements too.
In your case, detection of Fe wouldn´t be a problem.
EDS can be performed in a point and it gives you info about the composition of that point. Additionally EDS can be done over an area of interest, in this case you obtain a collection of spectra (one by each point scanned in the area) and elements can be shown in distribution maps. Imagine you analyzed an area that includes the background and a couple of NP´s. The EDS map would show Fe only on the place of the NP´s and say C on the background. Imagine your Fe NP´s are contaminated or mixed with Ni, the background would be still just C, and the area of the NP´s would show Fe and Ni.
Imagine that Fe and Ni gave different NP´s in your sample, well in this case some NP´s will show Fe and some Ni.
Hope it helps.
Remember, a machine can mix your chemicals, another can adquire your data, but it is your duty the duty of any researcher to interpret the data.
Best.
Hi !
From the received FESEM images, try to analyse the shape (morphology of your Fe NPs). It may be spherical, rod-like, poly-scaled etc. Also, select 3-4 best FESEM images having good focus, clarity, sharpness, and desired magnification. You can also highlight the shape with a marker and even show the exact dimensions using softwares like imageJ. Next, with the received EDS charts, try analysing each of it in terms of presence of impurities other than Fe in your case. Select one best chart with only Fe peaks or the one with minimum impunities present in your sample.
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