Bioequivalence and Bioavailability Forum

Dear Najat,

❝ 2. Part of the LC-MS/MS analysis involves performing system suitability at the beginning; the analyst modified the chromatograms to get a better base-line for the internal standard.

No problem if the re-integration (either manual, or by modifying integration parameters for some samples) was indeed performed to get a better integration, and all samples in the run were integrated in a similar way (when I write "similar" I don't mean the same parameters for all samples, or base-to-base for all samples, but the same "look" for samples with similar concentrations). Discussions should only arise if the integration was obviously biased.

According to the report of the 2006 Crystal City conference:
As part of qualifying instruments, performance of system suitability ensures that the system is operating properly at the time of analysis. System suitability checks are more appropriately used for chromatographic methods to ensure that the system is sufficiently sensitive, specific, and reproducible for the current analytical run. However, the system suitability tests do not replace the required run acceptance criteria with calibration standards and QC samples. System suitability tests, when appropriate, are recommended to ensure success, but are not required, nor do they replace the usual run acceptance criteria.

If the chromatogram integrations of the suitability test were indeed manipulated, that's quite bad; but if the calibration curve and QCs are OK you may still be able to save the run. If you re-analyse the samples, some authorities may even question your decision, stating that the first run was valid... Whatever you decide, should be properly documented.

Regards
Ohlbe