Chromatography Forum

if during my project i have done calibration of the system(lc-ms/ms) and the MRM of the already validated method changes by few decimal points what are the experiments that should be done?

Your question is not entirely clear - but for validation, the first question is are you working in a regulated environment? If so, there are requriements that must be met for a method to be validated.

In general, for your instrument, you need to demonstrate the range over which the method can be reliably calibrated, wich includes demonstration of linearity and reproducabilty over time. There are multiple ways of determining limit of detection. There are several ways of doing this - and the method of choice depends on regualtory environment.

If you have modified an existing method, you need to demonstrate bias in actual samples, or lack threof against the previous method - and if no bias was found, show how large a bias would have to be before you could detect it. Do not take it for granted that the abilty to generate a calibration curve with an equal or better correlation coefficient will get the same answers on real-life samples.

In the simplest case, you can run old and new methods in parallel for several weeks (sufficient samples for statistical anaysis, including within and between day/calibration variation and operator to operator variation).