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- Posts: 3
- Joined: Tue Jun 05, 2018 3:29 pm
I have rebuilt the flow cell and changed the lamp on the detector. For the separations unit itself I have changed the inlet filter, inlet check valves and the syringe.
After all of this I was able to get signal with retention times and back pressure and %RSD comparable to my other Waters 2695 with a 2996 PDA detector. However, the signal is not as strong as the system with the 2996.
The main problem is seen when comparing the same sample set between the two systems. In some samples with the new system there is no signal and on the system with the 2996 there is signal with the same samples. Also, on the new system the sample order doesn't match what is expected (The standard that is supposed to be twice the signal of the previous point is inverted. i.e. expected= 5 then 10, actual=10 then 5). The system pressure and inline degasser pressure is constant with isocratic runs with the new system when these erroneous results are seen. The same column was used for the runs on both systems.
Any suggestions would be very helpful as to the reason behind this reproducibility issue.
Thank you