Problems with a filter of Helium in Agilent MSD5975

[Analisis]

Hello,
Recently I have done a service in one Agilent 5975MSD, with Diffusion pump.
I have cleaned the Source and changed one filament in the source.
After that the autotune was ok and the equipment was functioning very well.
But the helium filter (Agilent CP17973) in the equipment was exhausted and we changed it after the service because we got a new one only after the service was done.
This filter comes filled with Nitrogen, so that is necessary to purge it when installed. I have purged it following the directions of Agilent. I set a 400ml/min flow in the split
but by mistake I have forget that the gassaver was on and then only 15 ml/min was the split vent.
After 89 minutes of purge I noted the mistake. In this moment the amount of N2/69 was more than 1000%.
I have set off the gas saver and purged the filter more than one hour. When monitoring the N2/69 I got that this ratio was going down rapidly to about 20%.
I have returned the equipment to the normal conditions with 15 ml/min in the split and 1 ml/min in the column.
The N2/69 went up to about 180%.
I thought that the problem was the N2 in the column so I vented the MSD and when vented have set the split to 400 ml/min and the flow in the column to 10ml/min. The MSD was vented and OFF. The N2 flowing out of the columnnaturally was going inside the Analyzer, but it was OFF. When the MSD will pump down again the N2 will go out without problem. I left the equipment purging for one hour.
After that I returned the equipment to normal settings: column flow 1 mlU/min and split flow 15 ml/min.
The N2 went down and finally N2/69 was 12%. It was late in the afternoon so I left the equpment to stabilize all the night long. Next day the equipment was with N2/69= 20 in the morning and later N2/69 = 12 again.
It was left some time again and today the equipment was with N2/69 at 9.xx% but N2/H2O = 142% or so.
Also the relation 502/69 is bellow 2% and I understand that it should be >2%.

I supouse that we only need to wait until all N2 goes out and the specifications are OK, but what do you think about this?

Thank you!!

[Henrylozano]

Hello,
Recently I have done a service in one Agilent 5975MSD, with Diffusion pump.
I have cleaned the Source and changed one filament in the source.
After that the autotune was ok and the equipment was functioning very well.
But the helium filter (Agilent CP17973) in the equipment was exhausted and we changed it after the service because we got a new one only after the service was done.
This filter comes filled with Nitrogen, so that is necessary to purge it when installed. I have purged it following the directions of Agilent. I set a 400ml/min flow in the split
but by mistake I have forget that the gassaver was on and then only 15 ml/min was the split vent.
After 89 minutes of purge I noted the mistake. In this moment the amount of N2/69 was more than 1000%.
I have set off the gas saver and purged the filter more than one hour. When monitoring the N2/69 I got that this ratio was going down rapidly to about 20%.
I have returned the equipment to the normal conditions with 15 ml/min in the split and 1 ml/min in the column.
The N2/69 went up to about 180%.
I thought that the problem was the N2 in the column so I vented the MSD and when vented have set the split to 400 ml/min and the flow in the column to 10ml/min. The MSD was vented and OFF. The N2 flowing out of the columnnaturally was going inside the Analyzer, but it was OFF. When the MSD will pump down again the N2 will go out without problem. I left the equipment purging for one hour.
After that I returned the equipment to normal settings: column flow 1 mlU/min and split flow 15 ml/min.
The N2 went down and finally N2/69 was 12%. It was late in the afternoon so I left the equpment to stabilize all the night long. Next day the equipment was with N2/69= 20 in the morning and later N2/69 = 12 again.
It was left some time again and today the equipment was with N2/69 at 9.xx% but N2/H2O = 142% or so.
Also the relation 502/69 is bellow 2% and I understand that it should be >2%.

I supouse that we only need to wait until all N2 goes out and the specifications are OK, but what do you think about this?

Thank you!!

My Advice is change it for RMSH-2.

[benhutcherson]

What are your typical values for these on this instrument?

I flow UHP N2 into my 5975(and 5971) when it's on "rest" and it honestly only takes ~30 minutes at a column flow rate of 1mL/min to basically clear all the N2(or at least anything but background from the inevitable leaks, etc) out of the instrument. Both instruments have diffusion pumps.

Do you have a hivac gauge? I actually find this one of the best ways to monitor the N2 levels in the instrument. The gauges are calibrated with N2, and since He doesn't ionize anywhere near as readily the gauge will read a lower value when flowing He into the instrument than N2 even if the actual vacuum is the same. Old HP and current Agilent literature specifies multiplying the hivac reading by 6 to get the "actual" reading for He. In the real world, on the 5971 with a head pressure of .5 psi(30m x .25mm column) at a 50º column temperature, which admittedly is a different flow rate for He vs. N2, I see ~2x10^-4 torr with N2 and an order of magnitude lower(2x10^-5 torr) with He.