I met suitability problem recently. I run two sets of standard 1,2 and 3 before and after samples. Each
standard contained 3 components. Everything was fine except component A in standard 1. The peak area
counts in std.1 before was only half of the one in std.1 after. That resulted in the correlation coefficient
for conponent A failed the criterion of 0.97. This happened to different analysts several times already.
However it doesn't happen everytime. I did experiment with a blank after sample and befroe the std.1 after
the sample to see if there was a carry-over. I didn't see any carry-over however. This problem bothers me
a lot and I can't figure out the reason. Could anyone give me any suggestions? Thanks.

Xiao