pre-mixed or non-pre-mixed

[ym3142]

This is a general question. Recently we found in several cases bubble was generated through the solvent inlet filter when the solvent was a premixed mobile phase (typically 80 Buffer and 20 ACN). A brand new filter or re-cleaned filter will solve the problem. But I never see bubble was generated in 100% organic or 100% buffer. So is the mixed solvent more likely to generate the bubble or I just conincidently had some dirty filters?

[Mark Tracy]

Air is much more soluble in pure organic solvents than in water. When you mix them you get a supersaturated solution of air. It spontaneously outgasses for a long time. You could briefly degas the mixture with vacuum/sonication if you like.

[ym3142]

Thanks, Mark

[danko]

A single remark: It’s true that one doesn’t see air bubbles in 100 % organic and to some extend in 100 % aqueous mobile phases. The reason is that the air bubbles are released upon mixing these i.e. in the solvent manager. That’s the last place I wish to deal with air

Best Regards

[ym3142]

thanks, Danko