Ayman Rabayah
☆    

Jordan,
2020-03-11 08:01
(231 d 04:32 ago)

Posting: # 21237
Views: 1,506
 

 Rejection of the standard curve [Bioanalytics]

Dear Colleagues
I need your opinions about the following:
we prepare the standard curve samples by using a human plasma lot, this curve composed from 8 non zero points, one blank sample and one blank sample with adding internal standard, the samples ordered to start with the blank then the blank with IS and then the non standard zero pints.
Upon analysis in the LC-MS/MS system, the blank sample with the IS found contains an interfering peak at the analyte retention time with more than 20% from the LLOQ response, while the blank sample is clean and the LLOQ response is normal (when compared to the previously analyzed runs). We conclude that the blank with IS sample was contaminated during handling while the other samples are not contaminated.

My question: is this case an enough reason to reject the standard curve and then to reject the run results? or can we accept the run results?

Thanks in advance for your thoughts.


Edit: Category changed; see also this post #1[Helmut]
ElMaestro
★★★

Belgium?,
2020-03-11 08:55
(231 d 03:38 ago)

@ Ayman Rabayah
Posting: # 21238
Views: 631
 

 Rejection of the standard curve

Hello Ayman,

» We conclude that the blank with IS sample was contaminated during handling while the other samples are not contaminated.

Or it could be crosstalk. Or your deuterated IS (if that is what you have) is not very pure but contains interfering amounts of analyte.

I could be wrong, but...

Best regards,
ElMaestro

No, of course you do not need to audit your CRO if it was inspected in 1968 by the agency of Crabongostan.
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