Hi Tharani,

Thank you for sharing your question with the RG community. XRF and EDS instruments (distributed by EDAX) use the specific scattering of X-rays for quantitative elemental determination. However, light elements such as H and C cannot be determined. Therefore you do not get a complete elemental analysis. Elemental analyzers are used for this purpose.

I wish you much success for your research.

Tharani Duraisamy

What is the question you're trying to answer? What does the elemental composition tell you? (Please not 'characterization' See: https://www.materials-talks.com/characterization-is-a-number-42-not-a-goal/). What defines 'the best sample' in your opinion?

Consider the amount of sample you have and whether any sub-sample is likely (or unlikely) to be representative of the whole. EDS will look at a tiny sample of the whole. With XRF you have the flexibility of larger samples and the ability to look from ppm to %'s.

Dear Dr Tharani Duraisamy

When I want full elemental spectrum data (light and heavy elements) using EDS I find both techniques are needed. Electron-based EDS favors the lighter elements, while x-ray based EDS favors the heavier elements. I have done co-analyses many times using an EDS system attached to my SEM, which also has an x-ray tube attached (micro-x-ray fluorescence).

Basically the data from both methods, done simultaneously, can be displayed within a single spectrum. However, because electron-based EDS tends to overpower x-ray-based EDS within the display, an adjustment needs to be made. This is done by reducing the SEM accelerating voltage to about 4-5 KV. Then run both systems (electron-based and x-ray-based EDS) simultaneously, thus producing a single spectrum where both systems are giving input.

Quantitation is possible if one has a well qualified sample to compare to. But one can create their own standard by analyzing (using the combined method) your unknown sample material several times. Average the data, then input that data into your EDS software as the standard. That self-created standard can then be used during your quantitation technique on any related material.

You may need to reference your Software Instructions for the creation of a standard, because each soft package (each brand) differs regarding operation techniques.

However, I think you will be pleased with the results.

EDX is best way for elemental analysis and this is enough for publication. If there is addition of ash or any soil samples then you should also do XRF for better investigations.

I hope this is helpful.

thanking you