Internal standard in HPLC CIPAC method

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7 posts Page 1 of 1
Hello,
I am looking for acetamiprid cipac method by RPLC in witch an internal standard is used.
Why they use internal standard ?
Thank you
The scope of the method says : '' The objective is to accelerate the ageing of a product by heating '' ;so the internal standard is added to check the change of acetamiprid against heat.
I think that what have you said is about the stability of the product, but the analytical method and most HPLC techniques use internal standard like AOAC.
My question why using internal standard. Can we use HPLC method with external standard, there is no extraction steps...!!!
If it's a compendial method (or, in fact, any validated method), then you must run it as written. If you use external standardization, then the modified method must be revalidated. it's your call whether it's easier to revalidate or to run the method as-is.
-- Tom Jupille
LC Resources / Separation Science Associates
tjupille@lcresources.com
+ 1 (925) 297-5374
Can you explain me why they use internal standardization ? In my opinion, we use it when we have extraction for exemple
Can you explain me why they use internal standardization
Who knows? As you point out, IS is most common when there is extensive sample work-up, but the developers may have modified an existing method, or may simply have been in the habit of using IS, or may have just thought it would be fun to do it that way for a change.

To be honest, when we teach Method Development courses, the question "why did they do it this way" often is answered by "I haven't got a clue, and I wouldn't have done it that way". :roll:
-- Tom Jupille
LC Resources / Separation Science Associates
tjupille@lcresources.com
+ 1 (925) 297-5374
tom jupille wrote:
To be honest, when we teach Method Development courses, the question "why did they do it this way" often is answered by "I haven't got a clue, and I wouldn't have done it that way". :roll:


100% agree.

Way back I once "fixed" a GC method where the peak of interest was on the solvent tail after sample preparation. Elimination of an unneeded dilution step fixed that readily, as the analyte to solvent ratio was then much more favorable so tailing was negligible.
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