During the EDX analysis of normal and demineralized bovine bone powder, the Ca & P element percentages were as expected in the normal bone and decreased with demineralization. The measured Boron was 26.5 % in the normal bone and reached 16.8 % with demineralization. Initially, boron is a trace element in bone, but this percentage is very high, and an explanation can't be found for that.
Amir,
boron is very difficult to analyse accurately by EDX due its very low energy. For any light element work it is absolutely essential that all the prerequisites for quant EDX are fulfilled: That is your sample must be flat, horizontal and polished to at least 1/4 micron, it should be conductive, the sample must be homogeneous within the interaction volume, you must have analysed your own standards on the same instrument. Any deviations from these and your results will only be good for qualitative work at best. If you are analysing powders then this will not work. With careful preparation, calibration and analysis it is possible to get some numbers out for boron, but you must have some idea of how well your system can cope with a known standard sample before attempting to work on 'real world' material. Additionally, trace elements by EDX, especially boron, is probably a lost cause.
It might help if you can show us your results, spectra, data tables etc. then maybe there may be more answers. Also what type of SEM, conditions, detector were used???
Dear My colleague Amir Mohammed Alsharabasy
peace be upon you
@Prof. Ian J Slipper
@Lijo Francis
I strongly concur with what mentioned before by Prof. Ian J Slipper. Really, the light elements of atomic number less than 6 can not be accurately detected by using the energy dispersive X-ray spectroscopy (EDS) because their very low energies. Therefore the researcher my be resorted to other techniques like EPS. But using a special detectors like AMPTEK DETECTOR (mod. XR100 or X123). You can choose Silicon-based which is good operating in the range 1 - 30 keV.
The attached paper (It has been Taken from a similar question and Dr. Lijo Francis replied on it) may help you, its title Is:
High spatial resolution energy dispersive X-ray spectrometry in the SEM and the detection of light elements including lithium.
https://www.researchgate.net/post/Why_Li_is_not_detected_in_EDX
Good luck
Prof. Ian,
Prof. Ahmed
Great thanks for your reply
I was just checking the change in the % of Ca and P as indicators for the decrease in the ratio of the bone hydroxyapatite with demineralization. The high concentration of boron was a strange result unlike expected.
Concerning the analysis, the technician performed the preparation and analysis, and all standards were tested using the same EDX instrument. But, based on the previous discussion concerning the Li analysis and the paper, it seems that my results aren't accurate for B due to its low atomic weight, and the total mineral content % isn't accurate as well; however, the analysis of Al, Mg, Na, Si and Sr revealed normal very low concentrations.
I have attached the analysis conditions and the results for the most important analyzed elements (Ca and P) in addition to Boron.
Kind regards
Thanks for the data, can you show us your spectra? Can you include the whole data table and not just for the elements of interest. This looks like energy calibration only, rather than beam calibration. It looks like these are the internal standards used in the Oxford Instruments software. Is this an ISIS system? Any comments on the sample preparation steps I mentioned above?
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