By Anonymous on Friday, June 4, 2004 - 08:37 am:

Hi, there,

I heard from people when they do quantitative analysis for drug quantitation for PK study, they usually bracket every sample, QC, Standard with blank runs. I think that is to make sure all the carry overs are washed away and good equilibration of column, and sometimes, if something is wrong, you can always go back to check the blank run ahead of that specific run and after specific run to see whether everything is OK,

Besides above reasons, is that any other reason they are doing this?

Thanks so much! I just want to double check my thoughts, thanks again,

jin

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By MG on Friday, June 4, 2004 - 11:12 am:

We bracket our QC's, and also run a blank after the high standard, but not every sample. If carryover is not observed after the high standard or QC's, we assume the autosampler wash cycle is doing its job. Perhaps if I had one of those "ballistic" 30 second methods, it would not be time prohibitive to bracket every sample and would be worth doing for the reasons you cite.

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By XZ on Monday, June 7, 2004 - 04:39 pm:

We do the same way MG does, I only heard once people do the "bracket" Jin mentioned: they had carryover problem, had to do a blank run after each sample to minimize carryover. Other than that, i don't know anyone bracket every sample.