Dear all, in reply to some of your comments:
Gerhard: Yes I have a very stable pressure throughout the whole run (20 bars) as I usually display its scale in my real time window, as for the data acquisition rate, I have to check that and get back to you as I usually leave this setting to the default value, but do you really think this would help?? and would it affect the rest of my profile in any way? Please elaborate more on this specific setting as I honestly don't know about it.. I only know about the detector response which I know could be increased if i have a noise problem, not the case here.
Mattias: No I only have a dual UV detector
HW Mueller: I use a 0.1M sod. phosphate + 0.1M NaCl buffer, I have also tried this buffer without the NaCl for method development purpose but the bump also existed.
As for the signal at 22min, please correct me if I'm wrong, but I believe it is usually sample related where its salts and all the completely retained components (in SEC case passing through all the small pores) and takes a whole column volume to elute, and what appears is usually not a peak but as you see in the profile is like a signal disturbance/deflection... am I correct?
i would like to try the air injection but wouldn't that insert air bubbles in the autosampler (also the system and column in general)? Unfortunately the software I use (LC solution) has no option to make a blank injection that involves the actual movement of the injector... I only have the option to insert a vial position of (-1) but this just runs the method with no injector movement, otherwise, the only option is to inject water as I had did and attached the above profile...
Awaiting your comments