Sample can not return to baseline for SD test

[slbmiss]

Why can't some samples return to baseline when I do the simulated distribution test? However the peaks sepreated very well. What's wrong with it? Do I need to change some prameters, like column flow, temperature program? I used 10 meters column and when I run D2887+PW655, I got the perfect sepctrum under the same condition.

[GasMan]

What happens if you do a blank run? If you just get a LARGE base line change, then your column needs to be conditioned. If you get peaks at the high end, then you probably have a contaminated inlet. What exactley do you mean by "when I run D2887+PW655", as D2887 is a method for up to C40 and Polywax 655 is used for methods going up to C90.

Gasman