How to treat the contaminated ALS (Agilent)

[thohry]

Hi all,

We are running Clentbutarol analysis on LC/MSMS 1200/6410. I do not know what happened 2 days ago: there is always a small peak of Clen even I inject blank (solvent or mobile phase). I have try to flush the ALS, but it gets down very slowly. I really want the clean the syringe of the ALS, but it seems it has to be disassembled.
Anyone have experience doing this task effectively with out taking things apart.

Thanks for any inputs

[Consumer Products Guy]

I don't have 1200, but have 1100s. On those, the loop and metering syringe are constantly being rinsed except when the ALS is in the bypass mode to pull up sample/inject.

I'd try an ALS rotor seal swap-over, to see if that helps. Maybe under Diagnosis/Maintenance run with high organic flow in the "bypass mode" to clean out those lines more. Those are flow paths that only get "used" during an injection cycle.

[mardexis]

CPG offers good advice. Nearly impossible to be the syringe assembly. A really worn rotor seal could do it though. It could also be getting stuck in your source somewhere and coming out whenever it sees organic mobile phase is you are running gradient.

Run a blank and look for it. If you see it then replace your rotor seal and run another blank. If you see it again then it is probably getting stuck in your source somewhere. If you don't see it but then run it comes back after running another standard then you might want to try a different rotor material. The agilent rotor is polyimide which can be problematic for amines. PEEK rotors offer lower carryover but slight less lifetime. Let me know if you want to try PEEK and I can help you out.