what do normal autotune reports look like? agilent 6890/5975

[new2GCMS]

Hi
I have a refurbished Agilent GCMS 6890/5975. I am new to GCMS and ran an autotune, but realized I don't know what the various things on the report mean and that I also don't know what normal values are. For example the H2O is at 4%. Where I worked previously, 4% was not good, but I've tried to look for leaks and cannot get the 4% to go down. i tried to bake the oven at 250degC and that also did not do anything for lowering my water %. I do not know what to do so any help would be great. I do not have a transfer line though I did try to lower the temp on Aux 1 to see if that would help. It did not.
thank you for any help you can give me.

[Bigbear]

How long has the system been pumped down? When open water gets into the system and is slow to dissapate. It should go down over time.
Agilent claims air/water < 10% is fine.
Your Aux 1 temp is the transfer line heater.

[new2GCMS]

The system has been pumped down since Thursday, so a little more than 3 days.

Could you tell me why the H2O value when down to 2% when I lowered the Aux 1 temp? I do not understand that.

Thank you for your comments.

[LCbob]

Hi

What is your Nitrogen % when you change the transfer line temp? Also what was the temperature of the GC oven in both instances.

Normally small leaks tend to manifest themselves at lower temperatures ( GC oven and transfer line ), this is due to the graphite/vespel ferrule at the end of the transfer line shrinking with the lower temp. What you are seeing is the the other way around.

Having said that difference between 2 and 4% is not too much, personally I would not worry about it if the nitrogen is low as well.

If it does worry you I suggest trying several times at a lower and upper temp to get some hard data.

[new2GCMS]

I have isolated the leak to the Agilent gasclean system that I bought to filter my He gas that I am running. It seems that the system introduces H2O (4%) and N2 (10%) to the system. with the Agilent GasClean system off my lines I get gas H2O at 0.8% and N2 at 0.6%.

I do not know why the GasClean system introduces so much troublesome gas into my system. Does anyone else know?

thanks for the suggestions.

[tlahren]

I don't know much about the Agilent "GasClean" system but most gas traps/sorbents are packed in N2 and sealed for shipping. Usually you want to purge them with He for quite a while before connecting to the GC if they are NEW. Even after purging for a few hours we would still see N2 and H2O at larger than normal levels for a few days.

I would just connect the traps to the He bottle and set the regulator so you can feel a gentle flow of He coming out the end of the lines and through the traps. Leave it like this for a few hours maybe more and then connect it to your GC.

Ty

[new2GCMS]

I took the gasclean system off and replaced it with a labclear filter and the problem went away. thanks.