Hi Melissa,

It’s not the greatest for the furnace tube (rather hard on the packing allowing the solvent thru) but the easiest thing to do next is hook the end of the column directly to the furnace tube. If that works then the problem is likely the diverter valve. If not then the tube could be the problem.

Before starting the above I’d double check He pressures etc and use a vial of solvent to check for bubbles at the open split. Same method can also be used to check flow is controlled by the diverter valve.

Feel free and continue off list if desired.

Cheers

 

Nick..

 

Nick Collins
President, MS Solutions Inc.

MS Solutions Inc.
12430 N Dowling Rd.
College Station
TX 77845

[log in to unmask] 
Tel: (888) ISO-IRMS (Sales/Service)
Tel: (888) 476-4767 (Sales/Service)
Tel: (979) 595-7625 (Direct)
Fax: (979) 705-9169

www.MassSpecSolutions.com (New instrumentation)

www.MassSpecSolutionsInc.com (eStore coming soon)

http://www.massspecsolutions.com/contacts/Contact.htm (Outside the USA/Canada)


From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of Melissa Bautista
Sent: Saturday, January 19, 2008 6:37 PM
To: [log in to unmask]
Subject: Re: [ISOGEOCHEM] GC-c-IRMS

 

Hi Nick,

Yes, there is signal to the FID. I installed a new furnace column last month. What would cause the cross-piece to suddenly clog?

Thanks

 

Melissa

 

 

----- Original Message -----

From: [log in to unmask]">Nick, MS Solutions Inc.

Sent: Sunday, January 20, 2008 10:40 AM

Subject: Re: [ISOGEOCHEM] GC-c-IRMS

 

Hi Melissa,

It’s hard to say without knowing a little more about the setup but assuming you have an FID and there is nothing on that either then there is likely a broken silica line inside the GC. If there is signal to the FID then it might be the furnace tube is blocked or the diverter valve is stuck and sending everything to the FID.

Cheers

 

Nick...

 

Nick Collins
President, MS Solutions Inc.

MS Solutions Inc.
12430 N Dowling Rd.
College Station
TX 77845

[log in to unmask] 
Tel: (888) ISO-IRMS (Sales/Service)
Tel: (888) 476-4767 (Sales/Service)
Tel: (979) 595-7625 (Direct)
Fax: (979) 705-9169

www.MassSpecSolutions.com (New instrumentation)

www.MassSpecSolutionsInc.com (eStore coming soon)

http://www.massspecsolutions.com/contacts/Contact.htm (Outside the USA/Canada)


From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of Melissa Bautista
Sent: Saturday, January 19, 2008 12:14 AM
To: [log in to unmask]
Subject: [ISOGEOCHEM] GC-c-IRMS

 

Hello,

 

I have been running FAMEs on our GC-c-IRMS using a 30m DB-5 column with 5m of guard column. The first six samples returned good peak resolution. After the sixth, I now get very poor resolution. Instead of well-defined peaks at the expected retention times, I'm getting hundreds of peaks at low amplitude (<100mV) throughout the run.

The GC method I'm currently using is as follows:

90-280C, 3C/min., 20 min hold; Flow rate 1.2 ml/min. He; Injection: splitless w/ surge.

Can anyone tell me what's happened, and how it might be fixed?

 

Thanks

Melissa D. Bautista
IRMS Research Technician
Centre for Coastal Biogeochemistry
Southern Cross University
P.O. Box 157 Military Road
Lismore NSW 2480
Phone (02) 66 269 565
Mobile 0431928278