Bioequivalence and Bioavailability Forum • m/z calibration range for mass spectrometer of LCMSMS

Debbie
★

India,
2011-08-30 19:38
(5024 d 02:47 ago)

Posting: # 7313
Views: 3,130

m/z calibration range for mass spectrometer of LCMSMS [Bioanalytics]

Hi,

In general, the mass spectrometer part of the LCMSMS system is calibrated using PPG standard with the m/z ranging from 59.1 to 2499.2
I would to like know, whether the usage of m/z of less than 59.1 (ex. 56.2, either Q1 or Q3) shall be acceptable in regulated bioanalysis?

Is the range of m/z used during calibration of LCMSMS shall be considered as fixed calibration range as like in other areas of bioanalysis?

Regards,

vinayshed
☆

2011-10-08 16:49
(4985 d 05:37 ago)

@ Debbie
Posting: # 7451
Views: 2,340

m/z calibration range for mass spectrometer of LCMSMS

Post reply

Hi Debbie,

The mass range is calibrated using PPG to set the ratio of DC current to RF frequency at selected m/z. A plot is generated later and slope and intercept are calculated. The user does not have access to these parameters as these are generated and stored by the software. Since the plot is linear, it can be extrapolated below 59.1 for all academic purposes. Normally regulatory requires the measurement to be bracketed within the calibration range. You will have to provide good scientific justification to the regulatory for their acceptance in case you really want to go below 59.1, though scientifically it is valid.

Edit: Full quote removed. Please delete anything from the text of the original poster which is not necessary in understanding your answer; see also this post! [Helmut]