Chromatography Forum

Mark, be careful that Caffeine does not contaminate your degasser.

I recall this experiment being tried at a major HPLC manufacturer that I used to work. The result was contamination of the semi-permeable teflon tubing inside the degasser with Caffeine - which was found to be leaching out for quite some time afterward.

Interesting. These same degassers then should be easily contaminated by ion-pair reagents or amines that are common mobile phase additives. I do know that early degassers (HP-1050 for example) were quite susceptible to contamination, but modern designs use different polymers and are much less likely to become contaminated. I have also seen cases (again older designs) of acetone migrating across channels of a degasser.

I had the idea of running water through channel A and the running the chromophoric reagent in methanol or acetonitrile as channel B. This would be more accurately simulate a real system. But maybe the response would be non-linear since the tracer could have different chromophoric properties when dissolved in different solvent mixtures.

The chromophore wouldn't change, but the steps would reflect the sum of that which was intended to absorb + the RI artifact inherent in the solvent switch, so I wouldn't recommend it.