Chromatography Forum

Hi. We have got an Agilent GPC50/ri detector with cirrus software. We are getting ghost injections, samples injecting and not getting a chromatogram, and samples injecting and getting poor response.

The dsu main pcb and injection valve have been replaced but do not appear to have resolved the problems. We think it could be the scheduler on the cirrus software

Any help/advice would be appreciated?

Since this detector has a very low volume flow cell it is maybe the geometry of the cell that makes it not easy to flush the cell. With a new instrument perhaps you have some airbubbles in the cell, stick on the window of the cell. Or the reference cell needs to be flushed. Do you operate at room temperature or at elevated temperatures? Is the pressure of the system constant? What flow rate do you have and what solvent? Guard column and how many GPC columns in series you have connected? Did you check for leckage at the column connections?
Good luck