LC/MS/MS system suitability

[hmelnickis]

Dear colleagues,

I have one problem with registration authority. We would like to register LC/MS/MS method, but authority asks for system suitability test. We write signal to noise for impurities.
My question is- what can I write in system suitability test for LC/MS/MS, maybe you can advise me any literature, where is described what is needed for a system suitability test LC/MS/MS?

[tom jupille]

Meaningful system suitability tests will be method specific: what do you have to run to assure yourself that the system is functioning and that the results will be meaningful?

Some or all of the following may be relevant:

- for the LC part:
- retention time window(s) for peak(s) of interest
- resolution requirements for critical peak pairs
- peak width or plate count requirements (in my opinion, redundant if you specify retention and resolution, but the regulatory people like to see them)
- tailing or asymmetry factor requirements

- for the MS/MS part
- noise levels at the m/z values monitored
- m/z calibration check

- for the entire system
- response (peak area) for a known standard
- linearity over the relevant range
- repeatability (RSD for a reasonable number of injections); may want to repeat this at various levels if analysis covers a wide range
- confirmation of LOD or LLOQ (S/N ratio of low-level standard)

The idea is to be able to tell ahead of time if the results will be bogus, and to give your analysts a target to shoot for if they have to adjust conditions.