ISTD, surrogates and recoveries

Adrian1980 6 months ago

Hello,
First time using MassHunter (version 12.0). I am trying to set a method for dioxin EPA 1613 and have doubts about surrogates, ISTD and how to calculate standard recoveries.

I have defined the standard added before sample extraction as ISTD, correct? and these are used to calculate native (target) concentrations.

But what about the standards added before injection? Are they surrogates? With these- I would like to obtain the recoveries of the standards added before injection, but I don´t know how 

Thanks a lot for your help!

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ron_tackett 6 months ago +1 suggested

If this is like EPA method 525.2 where you add an internal standard after extraction to measure the recovery of the extracted internal standards, you would add the extracted internal standards in to the…

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0 ron_tackett 6 months ago

If this is like EPA method 525.2 where you add an internal standard after extraction to measure the recovery of the extracted internal standards, you would add the extracted internal standards in to the quantitation database as surrogates (names differing like "istd surrogate" setting as a surrogate and have it use the non-extracted internal standard to quantitate it to calculate recovery.
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0 ron_tackett 6 months ago

If this is like EPA method 525.2 where you add an internal standard after extraction to measure the recovery of the extracted internal standards, you would add the extracted internal standards in to the quantitation database as surrogates (names differing like "istd surrogate" setting as a surrogate and have it use the non-extracted internal standard to quantitate it to calculate recovery.
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