Chromatography Forum

This system ran dry overnight. Its a 2695 connected to a 2475 FLD. Despite a new column, dry and wet primes, I still see about 1/100th peak response. (very low)
I purged injector, ran IPA through system and still no luck. I injected a standard on a 2487 UV which displayed a good peak response. But when I connect the 2475 FLD, it still has poor peak response? What compound can I inject on the FLD for a quick evaluation. ( i can't inject UV compounds like acetone and caffeine, like on the 2487)

any suggestions?
Also, can my original column be revived?

thanks

Have you tried removing the column, slowing down the pump, and just injecting a std into the detector to see if you have a peak?

Tryptophan may be a good compound to detect on your 2475...Ex 278, Em 355, I think. As far as the loss of response, it sounds like it could be a coincidental failure of the detector. I have an old 474 that is generally quite reliable, but has been known to fail completely and without any warning. It's done this twice, once in the middle of a run where the prior injection looked perfect and the following run was just baseline. Both times required shipping back to Waters for rebuilding. As expensive as it is, I won't run an FD without a service contract.

thanks for the info. I got the air out of the fld by pumping IPA at a low flow rate. I saw synchrounous baseline noise (spikes) so I knew it was the pump. Changed the check valves and all good now.