Hello, we are using a thermo TSQ Fortis triple quad mass spec with a ultimate 3000 hplc system from thermo as well.
We are having a lot of issues with the baseline, it suddenly starts going up and it makes the chromatogram look like a thick black line with really high intensity signals (like x10^6).
Sometimes it goes down during two inyections quickly, taking between 15-30 minutes. Other times it stays up for a long time and it has us dumbfounded. We don't know what else to try. We pause the reading of the MS part and it goes down easily and stays like normal, other times it shoots back up again without even starting an inyection.
Any suggestions?
Thanks in advance
You didn't mentioned the composition of Mobile Phase.
Whether you added formic acid, TFA, acetic acid etc. to pH adjustment.
Then check
1. if you added formic acid in your mobile phase, mostly used in 0.05%-0.2% conc., if problem occurring in this, check your chromatogram by running a sample in 0.05 % TFA containing mobile phase, or with other pH modifiers.
2. if you are facing same problem in all of the above mentioned pH modifiers, you can wash your column by
- setting column heating temp. (40-50 degree, based on column limit) with pure aqueous and then pure organic solvent (MeOH).
- also try reverse column wash.
- also check the same mobile phase by changing the column, to check if the same baseline problem occurring or not.
Anil Kumar Hello, thanks for the suggestions. I didn't mention the mobile phase because it happens regardless. Mostly we use water and MeCN with formic acid.
We have washed our column and changed it but the issue remains.
Now we are considering the pump as a possible source of the problem and experts are comming next week to check the hole system.
Have a check with TFA in place of Formic acid.
Try washing the pump by removing the column, with high flow rate, using the hot water of 70-80 degree. Also use ACN at last.
At last, contact Service engineer.
Good luck.
🙂
Start at the beginning. Troubleshooting step 101: REMOVE the HPLC column and install a restriction capillary in its place so you can operate the system at an appropriate system back -pressure. Doing so will allow you to properly flush and test the pumps, flow path and detection system for correct operation. *A restriction capillary is a required "tool" to have for anyone who operates or maintains an HPLC, LC-MS or LC-MS-MS system. BTW: Please do not add or substitute TFA for formic acid!!! TFA often results in the contamination of the MS source.
"The HPLC Restriction Capillary; Troubleshooting, Qualification and Running Without A Column"; https://hplctips.blogspot.com/2018/04/the-hplc-restriction-capillary.html
"Diagnosing & Troubleshooting HPLC Pressure Fluctuation Problems (Unstable Baseline)"; https://hplctips.blogspot.com/2014/01/diagnosing-troubleshooting-hplc.html
Noel Alonzo if you have a UV detector inline with your MS (and you should, as setting up and using an HPLC w/o a UV detector inline to the MS greatly limits its use), then use the UV detector to help troubleshoot the problems. A MS detector alone is not very useful for troubleshooting flow path, pressure or other related problems.
- Badges
- Science topic
- Similar topics
- Geoscience
- Atmospheric Sciences
- Atmosphere
- Air