Chromatography Forum

Ok, so you're saying that there is a leak based on the fact the baseline is smooth, but what exactly am I looking for?

What I said is that if by some single action the baseline became smooth the fault was caused by what you corrected with this action (except if the problem is corrected spontaneously just at that time).
You are looking for faults in the plumbing.
I still wonder what spectra look like of different portions of this "baseline".

I could some pics of the spectra, if you'd like to see them.

If you can´t imbed them here you could explain them. In my experience air peaks have produced specs which just rapidly come down from 200nm, staying higher to at least 300nm (didn´t go above) than a "better" baseline. Compounds with a maximum above 200 nm show that maximum, of course.

I will place the spectra here if I can. I'm not sure I could explain the spectra satisfactorily.

Here is the chromatogram:

Just looks as if you didn´t leave the system alone, injecting stuff, including air, adjusting the baseline.... instead of letting it come to equilibrium before assessing it (in other words, this discussion has dragged on, apparently because you didn´t really tell what you did). What about the UV specs?

The UV specs are flat baselines, except for the injection peaks.

The other spectra show a baseline that is elevating, then dropping when I've done nothing to it and let it sit. I was very careful not to inject air, but that doesn't mean I didn't.

My biggest problem right now is inexperience. My apologies for letting this drag on as long as it has. In the future I'll try not to inundate everyone with problems that I should be solving myself.

Thanks to everyone who has helped me, especially Mr. Mueller.

Just play around a bit more, you will get the hang of it.

Hi Steve,

I was wondering, you mentioned you had the U-610 BPR from Upchurch... that one is actually rated to 750 psi. Did you actually have the U-605 (I hope) which is rated to 40 psi? You'll know by the label on the body of the BPR or by the colors of the cartridges. The 750 psi cartridge has a black body and blue end cap, the 40 psi cartridge has a tan body and blue end cap. If you did have the 40 psi cartridge inline and the pressure was much higher, it sounds like a defective part. You might want to contact Upchurch's customer service department about returning the part.

Thanks,
Caitlin
Upchurch Scientific
R&D Chemist

Caitlin,

It was the black body with the blue cap. I thought I was ordering the 40 psi cartridge, but it seems I didn't. The part number was given to me by someone else who had a similar one, but she had the 40 psi cartridge.

Steve