Chromatography Forum

I need help from you,
In GPC experiments, the chromatograms have a bad baseline. That usually happens after the first peak more intense, the baseline does not resume its original position (5mV), but lowers to zero, so I lose the information of the sample. The problem is more pronounced for the IR detector. I use polystyrene column for analysis of polymer samples.
Thanks

Impossible to tell without details.
What instrument?
What detactor(s)?
What column(s)? What pore sizes? What dimensions?
What mobile phase? Flow rate?
What temperature?
What injection volume? What concentration? What diluent?

All of those can have an effect.

I need help from you,
In GPC experiments, the chromatograms have a bad baseline. That usually happens after the first peak more intense, the baseline does not resume its original position (5mV), but lowers to zero, so I lose the information of the sample. The problem is more pronounced for the IR detector. I use polystyrene column for analysis of polymer samples.
Thanks

The most critical parameters doing GPC are; Temperature and flow rate. Achieving a good baseline for 30 minutes before injections is a must.Do a flow test , and set a temperature of 5Deg above the ambient on the cell, and column. Then run your baseline. If that looks good, then make an injection and go onwards.