Combipal z-axis errors

Discussions about GC and other "gas phase" separation techniques.

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I'm certain this has been discussed in the past, but I can't seem to find a post. We have a Varian 3800 with a combipal attached for headspace analysis. We are having problems with our 20 mL vials. The arm is having difficulty returning them to the sample tray. I believe it's because the caps are misaligned. We are using a restek brand of crimp caps. It appears that slight angles on the caps are causing our problems. What's recommended for this system?

I use P/N: 502 370

from: on all of my combipal-type samplers (old LEAP, Agilent, EST Analytical). All rely on a magnet for transporting the vials from the tray to the incubator and back, etc. These are nice because they're a combination of aluminum and steel. You can decrimp them to dispose of the contents of the vial before trashing the vial.

I get them through VWR Scientific but it's always a bit of a hassle because they don't appear in the VWR online catalog. We always have to refer back to the old PO number to get the right VWR P/N.
The only explanation I can think of is you are using nonmagnetic aluminum crimp caps or you are not putting the magnet on the injector or your programmed coordinates are off.
MACHEREY-NAGEL #702774 works well for me.
Check that you are not crimping the caps too tight, or holding the crimper at an angle to the vial when you crimp.

Peter Apps
After trying to perfect our crimp technique, we decided to switch to screw top vials. Both vial types were purchased from Restek. It seems like screw top has fixed our problems for now. But, I'm more wary that we are not getting a good seal.
6 posts Page 1 of 1

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