avatar: moodyvv
moodyvv
2 posts
Replied to moodyvv's post on October 11th, 2012

Ok Guys,

This is the first time I am using GC. We have a GC-MS relatively new but was not used since 2 years.

When I did the system check it failed the 28/69 peak. One of the CSR told me to remove the column and wipe it with acetone and reconncect column change the o-ring, and septum. Septum and O-ring were fine but while reconnecting the column the nuts (connecting the column to the injector port) will not hold the column and column basically falls apart from the nut and the ferrule.

I was following the protocol from Schmidzus manual about connecting the column but the ferrule.

Any suggestions?

 

Moodyvv

 

avatar: LabWrenchEditor
LabWrenchEditor
1835 posts
Replied to moodyvv's post on October 12th, 2012

Hi Moodyvv,

In order for our LabWrench team to better assist you in finding the answer to your question, could you please specify the model of Shimadzu GC that you are referring to?

Best Regards,
Kylie

avatar: moodyvv
moodyvv
2 posts
Replied to LabWrenchEditor's post on October 17th, 2012

Thanks,

Sorry for the delayed response.

Ours is GCMS QP2010.

 

Moodyvv

avatar: LabWrenchEditor
LabWrenchEditor
1835 posts
Replied to moodyvv's post on October 18th, 2012

Which size of column (0.1 / 0.25 / 0.32 / 0.53) and which ferrule (0.4 / 0.5 / 0.8) are you using ?

Thank you to Sephane M for providing this response to LabWrench via LinkedIn

avatar: LabWrenchEditor
LabWrenchEditor
1835 posts
Replied to moodyvv's post on October 18th, 2012

Stephane's question is important. We usually focus on the id of a capillary GC column. However columns of different id's also have different od's. for example a 0.25mm id column has an od of 0.4mm. Whereas an 0.32 mmid column has an od of 0.5mm. The GCMS systems use vespel ferrules which are quite rigid and the hole size has to be matched to the appropriate capillary column. The tapered end of the ferrule has to be facing back into the nut so that the two flat surfaces face together. Newly fitted vespel ferrules have a tendency to shrink a little after the GC oven has been temperature program cycled a few times. So in the first few times of cycling a new ferrule you may need to tighten it up a little to restore the seal. The peak monitor window of GCMSsolution is a live and dynamic way to monitor relative peak intensities on the fly while making changes like tightening connections etc

Thank you to Bruce F for providing this response to LabWrench via LinkedIn

avatar: LabWrenchEditor
LabWrenchEditor
1835 posts
Replied to moodyvv's post on October 18th, 2012

It sounds as if you failed to replace the ferrule in the column nut or did not tighten the column nut sufficiently. You need to ensure you have the correct ferrule for the column diameter you are using. If the 28/69 ratio is high, this is indicative of a leak. The leak could be anywhere in the carrier gas supply pathway, the inlet, column connections or a poor seal on the analyzer.

Thank you to Dan S for providing this response to LabWrench via LinkedIn

avatar: LabWrenchEditor
LabWrenchEditor
1835 posts
Replied to moodyvv's post on October 23rd, 2012

Also, did you try doing a couple heat cycles? Since the ferrules used for MS are not graphite they don't initially tighten on the column. Typically running the column oven up to you method max (200 or above and hold for about 5min) and bringing it to cool (hold for 5min) will do the trick. I would try the heat cycle 3-4 times to make sure your ferrules are tight on the column. Also, how high is 28? How long have you had the system on?

Thank you to Nicole L for providing this response to LabWrench via LinkedIn