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- Posts: 1
- Joined: Fri Jan 03, 2025 8:23 am
- Location: Czech republic
Hello,
we are dealing with phosphonic acid contamination (probably) in our IC-MS system. We are using ICS-3000 coupled with MS Sciex Qtrap 4000. Phosphonic acid is one of our analytes when we analyze pesticides. Column is AS-11HC with guard column AG-11. We use KOH cartridge eluent generator. In the method, there is eluent gradient - from 10mM to 60mM and back to 10mM.
There is how it should look like (june 24) in blank sample:
Then suddenly it started to looks like this (october 24)
And now it´s like this, so it´s getting worse and worse (april 25)
It´s only on this two masses: 80.8/78.8 and 80.8/63.0
We manage to isolate the problem to IC itself:
- it´s not the sampler - when we bypass it, the peak still appears
- it´s not the MS, because the peak shifted when I changed the flow through the system from 0.3 to 0.35 ml/min.
- it´s not the DI water - we scanned it using TOF and there are no signals on the H3PO3 mass and we also tried to use store bought LC/MS quality water with same result.
We tried brand new column and guard column - same result
We tried brand new suppresor - same result
We tried to bypass CR-TC and gradient mixer - same result
We tried to scan the H3PO3 masses without running the whole method - just scanned what goes from IC to MS:
1) no KOH (turned off in Chromeleon, but connected to system) - the signal is very low around 500
2) 10mM KOH - the signal is getting around 15 000 with sudden peak after +-5 minutes to 100 000, than back to 10 000
3) 60mM KOH - the signal is same as 2) and sudden peak also appears after +-5 minutes with intensity up to 200 000, than it goes down to 10 000, which is stil very high.
It has to be some kind of contamination. To me it seems that it sits somewhere in capillars or somewhere else and then with KOH it is slowly eluting from the system, but something has to generate it right? Everytime the KOH gradient starts to get higher, the peak appears, so it´s in every sample we run.
Do someone has any idea what it could cause this? And even better how to solve it? It´s possible to flush the whole system with something to get rid of it?
Thank you for any idea!
KS
we are dealing with phosphonic acid contamination (probably) in our IC-MS system. We are using ICS-3000 coupled with MS Sciex Qtrap 4000. Phosphonic acid is one of our analytes when we analyze pesticides. Column is AS-11HC with guard column AG-11. We use KOH cartridge eluent generator. In the method, there is eluent gradient - from 10mM to 60mM and back to 10mM.
There is how it should look like (june 24) in blank sample:
Then suddenly it started to looks like this (october 24)
And now it´s like this, so it´s getting worse and worse (april 25)
It´s only on this two masses: 80.8/78.8 and 80.8/63.0
We manage to isolate the problem to IC itself:
- it´s not the sampler - when we bypass it, the peak still appears
- it´s not the MS, because the peak shifted when I changed the flow through the system from 0.3 to 0.35 ml/min.
- it´s not the DI water - we scanned it using TOF and there are no signals on the H3PO3 mass and we also tried to use store bought LC/MS quality water with same result.
We tried brand new column and guard column - same result
We tried brand new suppresor - same result
We tried to bypass CR-TC and gradient mixer - same result
We tried to scan the H3PO3 masses without running the whole method - just scanned what goes from IC to MS:
1) no KOH (turned off in Chromeleon, but connected to system) - the signal is very low around 500
2) 10mM KOH - the signal is getting around 15 000 with sudden peak after +-5 minutes to 100 000, than back to 10 000
3) 60mM KOH - the signal is same as 2) and sudden peak also appears after +-5 minutes with intensity up to 200 000, than it goes down to 10 000, which is stil very high.
It has to be some kind of contamination. To me it seems that it sits somewhere in capillars or somewhere else and then with KOH it is slowly eluting from the system, but something has to generate it right? Everytime the KOH gradient starts to get higher, the peak appears, so it´s in every sample we run.
Do someone has any idea what it could cause this? And even better how to solve it? It´s possible to flush the whole system with something to get rid of it?
Thank you for any idea!
KS
Katerina S.
