Hi dear colleagues
Why is sometimes the sum of concentrations of oxides (and elements) in the results of XRF test less than 100%? Is it correct to mention as is in the paper?
For example, the sum of the concentrations is 61%.
Best regards.
Please have a look at a similar question; the answers will help you:
https://www.researchgate.net/post/Why_is_the_sum_of_all_calculated_elements_before_normalization_is_much_less_than_100_in_XRF?_iepl%5BgeneralViewId%5D=mYCRGlDQud8QAW8Xlmfkyj4F0g7tl8LXyc5U&_iepl%5Bcontexts%5D%5B0%5D=searchReact&_iepl%5BviewId%5D=aCVqR0A2NLlKPSaN4TvMF66LojNStGRZe28y&_iepl%5BsearchType%5D=question&_iepl%5Bdata%5D%5BcountMoreThan20%5D=1&_iepl%5Bdata%5D%5BinteractedWithPosition2%5D=1&_iepl%5Bposition%5D=2&_iepl%5BrgKey%5D=PT%3A569ded436143252df38b459a&_iepl%5BtargetEntityId%5D=Q%3A569ded436143252df38b459a&_iepl%5BinteractionType%5D=questionView
Thank you so much Dr. Gerhard Martens for the very useful link.
Dear Colleague, I noticed the same in my just concluded research work about a plant seed. I was eager to know why because the sample was sent out of my territory for analysis but I was told since the analysis was done in term oxides, there is every possibility of certain portion of the sample which is free oxygen at high energy level is not read by XRF.
Many thanks, dear Dr. Segun Michael Abegunde for sharing this useful information. Is it correct to mention as is in the paper?
Dear Dr Mohammed Salah Nasr, am not sure if that will be appropriate because I never see such in any article and I do not think oxygen will be 100% responsible for the loss in the sample, so what happen to the remaining portion?
Thank you dear Dr. Segun Michael Abegunde for your attention. As I read, the LOI may also responsible for reducing the sum of concentration below 100%.
Thank you Dr. Zineb labaali for adding an answer. I tested four materials, organic and inorganic materials. The sum of oxides were about 25% for organic material and about 61 to 88% for inorganic substances. Is there a practical procedure to solve this problem (after test) and to correct the sum of oxides to 100%?
Best Regards
Think Oxides is just a equivalent component for elemental analysis. However, this do not mean that all elements are associated to oxigen, this is just a representative way to show the result. If you are using Fundamental Parameters, the sum of all components should be 100%. If you are using empirical calibration curve, so you can express results as metallic elements.
Many thanks, dear Dr. Isam Mohamad Ali for adding your valuable answer.
In your raw sample you had a carbono-apatite with phosphorus and carbon that are subjected to glass fusion to prepare the sample for XRF. This process converts any C to CO2- which is evolved as a gas prior to measurement. The P is most likely present as P2O5 which should remain in the sample. However XRF does not measure any evolved gases. The lab will try to compensate for this by ignoring evolved gases and recalculating for most likely oxides, a process called 'normalisation'. High carbon samples such as limonite, and carbono-apatites are not well suited to XRF analysis because it biases any carbon containing samples to a higher grade by this process.
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