analyst 1.4.1 datafile problem

[alpesh]

dear all
i am using API LCMSMS and analyst 1.4.1 software version. one strange thing i have observed many times is that when i acquire run of sample, immediately followed by the same sample but with different datafile, i am getting noticeable change in area of drug as well as internal standard for the said sample. Has anybody observed the same problem???

[sassman]

It is normal for there to be a significant change in instrument response for the first few samples when using electrospray MS. We usually run several blanks before starting the samples to allow the instrument to settle down. If you are getting this behavior even after the machine has been running for some time, I would suspect a problem with the autosampler or possibly something wrong in the source. Check that the spray is smooth in the source to be sure that is not the problem

[alpesh]

Dear Sassman, my question was entirely different than what you have interpreted. I have problem with datafile in analyst software. we always give first few runs to settle down instruments. But when i start actual sample analysis with different datafile immediately after those stabilization runs, i got different response.
have you ever experienced that phenomenon?

[sassman]

Maybe I am not understanding your question. If the problem is changing response, that is certainly due to instrument conditions and is NOT a software problem.