Poor Sensitivity with Nitrogen Carrier Gas

Hi all,

I have been trying to change our 8890 GC carrier gas with a FID from helium to nitrogen.  To verify the change went well I first prepared a test mixture of lab solvents (methanol, acetone, pentane, dcm, isopropanol), ran it using He, then ran it using N2.  When using N2 I saw a 10x weaker signal than compared to when it was run using He.  I swapped back to He, reran the sample, and obtained the same results as before. 

I tried with different methods, a different cylinder of helium, using the method translator tool, and running a test mixture provided by a vendor yet the signal has always been 10x worse with nitrogen.  This was all done using an autosampler that I know is working fine, an injection volume of 0.5 uL, and a split ratio of 100:1.  To see if the issue was instrument specific I swapped a 7890b GC with a FID in another building from helium to nitrogen, tested my sample using both carrier gasses, and this time the nitrogen provided a slightly stronger response.  

Has anybody else encountered anything like this?  Is there some change I need to make that is specific to the 8890?  I thought the only necessary change was to go into the moldules section of the method and specify N2 as the carrier gas.  Is there anything else that has to be done?  When using nitrogen and not changing the method at all, my retention times and area% for each peak are very similar, it is just the total area count that has tanked.

Thank you ahead of time for your help.  


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