CAS Increasing background in long runs

Hi all,
We recently ran a larger than usual study and I have recently switched from the HT injector and water to the (not so new) WB injector and CAS. I ran for over 8 hours with multiple stops and starts to preserve files, but later realized my background on CD3 on 148Nd (specific to 148Nd and also 145Nd) was increasing drastically and converged over time with my signal. This left the last 3rd of my acquisition worthless.
I have done many runs in the past and hadn't seen this with water. I was curious if anyone else has a similar issue with the 140's range of metals with CAS?
Thanks,
Chad
We recently ran a larger than usual study and I have recently switched from the HT injector and water to the (not so new) WB injector and CAS. I ran for over 8 hours with multiple stops and starts to preserve files, but later realized my background on CD3 on 148Nd (specific to 148Nd and also 145Nd) was increasing drastically and converged over time with my signal. This left the last 3rd of my acquisition worthless.
I have done many runs in the past and hadn't seen this with water. I was curious if anyone else has a similar issue with the 140's range of metals with CAS?
Thanks,
Chad