Do report as dried or as-is that is the question?

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DeKay's picture
Do report as dried or as-is that is the question?

I have a question regarding the appropriateness of reporting assay values from a titration on the "as-is" basis or "dried basis".
When this is not specified in the compendia (ex USP,EP,ACS) what are the general analytical rules. From what I have gathered when there is the possibility of significant moisture in the sample (ex 6-9%) the using the "dried basis" is suitable if accounted for by the determination of moisture/LOD? Yes? No? Maybe?

Let me know. Thanks in advance for your comments

Dr. Analytical
Dr. Analytical's picture

You are correct.  When a significant amount of moisture is present (usually more than a few %), then a correction for dry weight is usually the best approach.  The reported value will be larger.

Remember, loss on drying and moisture content (e.g., Karl Fischer) will usually give the same answer, but not always, since they measure different parameters.

Crown's picture
we sold some Fumaric Acid

we sold some Fumaric Acid which was described as 99.5% on a dry weight basis , our client has interpreted this to mean purity , can we have your comments on this