Chromatography Forum

Hi Folks,

I need some help.. I run fermentation samples for analysis using a BioRad Aminex HPX-87H column with a 0.02 N H2So4 eluant. Very low pH

I recenty pickedup an Agilent 1100 HPLC with a RI detector. I have an older 1049 RI running on my other machine and we have no baseline issues with it. With this new one I constantly get a negative baseline drift, it starts at 0 and always ends in the negative.. Here is what it looks like :



Any ideas how I can fix this up?

Also, I get a small negative peak after my large sugar peaks. There are 4 sugars that have very large peaks. Any of my other compounds do not show these negative peaks.. any ideas?? I increased the temp of the detector from 35 C (my old setings on the 1049) to 55 C (closer to my clumn which is at 60 C), and these have decreased, but they are still there..



I would appreciate hearing about any ideas you might have that I could try to fix these issues..

Thanks in advance for all your help..

- Hubert

Ideally, your mobile phase, column, and detector temps should all match. Since increasing the detector temp to be closer to the column temp seems to help, I'd go all the way.