Chromatography Forum

Hello, It´s nice to find a chrom- forum so good...thanks for maintain it...
I´d like you to answer a theoretical question about MS quadrupole detectors: I know that simonizing MS detector is the way of calibrating it, and that each time I do “Autotune”, I`m changing the voltages of lenses and that´s the main cause of doing parametrical calibration each time (constructing a regression curve).
At work, they have ask me to make a study of intervals of regression function for each analyte in order to enclose an interval of good performance for linear term and constant.
In my opinion, that´s not possible for MS detectors, but I need to demonstrate it and to provide evidences or written documents, such as books or papers (signed for someone more famous than me ) that make me able to prove it.

Thank you very much

You've lost me there mate.

You can determine the linear range of the MSD detector, but as you say you need to calibrate vs a standard each time you want to quantitate as the new tune parameters will change the detector response.

The biggest problem is that some compounds just will not be linear, but have a quadratic response.

I find that using the EPA method of injecting a tuning solution each day or other time interval to verify the instrument is still within tune parameters instead of running the autotune or other tuning method often is much better, because you will not change the lens voltages often. Once you do change the settings you will need to recalibrate.

Are they asking you to provide a time interval between recalibrations or are they asking for the concentration range in which the instrument will remain linear in response?