Extracted chitin was subjected to Kjeldahl method, the result of nitrogen level obtained was 1.7 % ; however, EDX elemental analysis present various values of nitrogen form 3 to 6 %.
How can we explain this difference?
is each method present specific meaning of percentage?
EDS is not among the best methods for quantitative bulk analysis, and, even worse, it is tough to apply to organic specimens. You need standards, you need well trained operator. So, forget your EDS results for N in chitin, they are definitely wrong.
Vladimir Dusevich I read most your answers in researchgate and I'm really impressed by it :) .
I think that N% obtained by EDX present a weight percentage and that is not a comparable to CHNS result which mybe present a different meaning of N%.
I received a question from the reviewer, he said that nitrogen level of chitin obtained by EDX is very high (I guess he think that the meaning of this result is the same of the result obtained by CNHS ), So, kjeldahl method was performed and the values are quite different.
Furthermore, I found in the literature commercial chitin as standard material, his nitrogen level between 7-8 % determined by CNHS elemental analysis, but in EDX the value vary from 11 to 15 %. how we can explain this?
A. K. M. Atique Ullah
we totally agree, so it's too diffuclt to use EDX for quantitaive analysis as Vladimir DusevichI said.
Proper quantification of light elements (such as N) by EDS is a tough task. It requires use of standards and good understanding of the technique. I believe that your results (as well as results from the paper you mentioned) were obtained by means of standarless analysis, which produces huge errors in light elements analysis. If you need bulk analysis of light elements (not a microanalysis, where EDS excels), use other methods, discard EDS results.
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