Trouble getting agilent inlet to be leak free (mz/51)
Posted: Mon Jan 23, 2023 4:45 pm
I am working with an Agilent 7890B GC system and lately I have been having some troubles with getting it be leak free. I have a Restek Rtx DHA-50 column installed. It is 0.2mmID and 0.5um df. My procedure to install the column to the inlet is to add a 0.4mm ferrule (Restek cat #20239), install the ferrule onto the column with a septa holding the column nut in place. Then I make sure to cut the column and have the 5mm of column above the ferrule before tightening the column nut onto the inlet. After finger tightening I tighten a couple turns with a wrench and then increase the inlet temp after verifying no leaks with an electronic leak detector. Then I do a leak check by scanning for mz51 and spraying duster at the inlet. I have regularly been seeing peaks for 51 when I spray the inlet. I have tried tightening the nut on a little more but it does not seem to fix the issue, and I am afraid to over tighten. I've tried installing new ferrules but each time I run into this issue.
My guess is that the way I am installing the ferrule onto the column is not ideal, and probably I could be pre-swaging it somehow and this could help to eliminate the leak. I wanted to reach out here to see if someone else ever had a similar experience and what they may have done to fix the issue. Any help is much appreciated, thanks!
My guess is that the way I am installing the ferrule onto the column is not ideal, and probably I could be pre-swaging it somehow and this could help to eliminate the leak. I wanted to reach out here to see if someone else ever had a similar experience and what they may have done to fix the issue. Any help is much appreciated, thanks!