column installation varian saturn 2000 gc ms- injector end

[sideline]

Hello all,

Quick question regarding column installation in the Varian saturn 2000. The manual gives me a recommended distance for the transfer line end but doesn't mention how far the column should be inserted into the injector end. I tried doing it by feel but not sure if it supposed to touch the end or if it should be pulled back a little bit?

Any suggestions?

Cheers,
Aoife

[Peter Apps]

How far in the column has to go depends on what type of inlet you have, and the instructions are in the GC handbook not the MS's. It definitely must not touch the septum at the top of the inlet - the push it till it stops advice is for installation into an FID not an inlet.

Peter

[sideline]

Hi Peter,

Thanks for your reply. The manaul I have is a hardware operation manual and seems to cover both the GC and MS components. It tells me how to remove the column from the inlet but gives no instructions about the distance required when I re-insert it. We always do split injections so I imagine the inlet is designed for split (not sure if I am using the right terminology so apologies if I am not!). It is not touching the top at the moment, it is about 5mm short of the top I would say...

Cheers,

Aoife

[Peter Apps]

I have never seen a Varian manual that did not have column installation instructions somewhere. The tip of the column has to be near the bottom of the inlet liner, not the top, otherwise how is the sample supposed to get into the column ?. With the column tip 5 mm from the septum it is actually above the point that the sample is injected, and all that gets onto the column is what manages to diffuse against the stream of carrier gas through the inlet. As a rough guide for most Varian inlets measure the distance from the tip of the inlet stem to the roof of the oven, add 5 mm and insert the column that distance. It will not be exactly right but at leat you will see a chromatogram.

Peter

[sideline]

Hi Peter,

Thanks for your reply. I will try that. I am getting a chromatogram at the moment but the peaks are smaller than I would expect so your explanation makes perfect sense

Cheers,
Aoife

[Ultimate Science 101]

Aoife --

Assuming you probably have one of two most common Varian injectors, the 1177 or 1079... From the back of the column nut measured to the end of the column length being installed into the injector, the distance should be 37.5mm for the 1177 and 75.0mm for the 1079. If you hit the injector button on the keypad of the Varian 3800, it should tell you which injector(s) you have installed.