Chromatography Forum

Hi. We attempted to switch out the autosampler and pump module on our Beckman Gold system with refurbished ones, and when things didn't work out we reattached the old autosampler/pump. Now all peak areas have approximately doubled, for control as well as test materials. It also looks like the first peak has been 'swallowed' by the injection peak. I'll be happy to post more details, including chromatograms if needed; it is just kind of a hassle because I have to transfer from another computer.
Pump pressure is around 1.5 Kp (a bit high for us but not too high), as far as I can tell the injection volume is the same. We changed the guard column before restarting with the original modules and noticed it was very dirty.

Essentially, all we did was take off and then reinstall the autosampler and pumps, and now we have this problem. Any ideas greatly appreciated.

You may want to check your configuration of the autosample loop volume in the instrument setting. Make sure the physical loop volume matches the software configuration.

Richard

Thanks for getting back, sorry for the long wait to reply. After recalibration, the response factor for the one method in question hadn't been changed, by chance it resulted in almost exactly twice the peak area. Thanks for the feedback!