More Technical Service “Red Flags” – GC

Just like in my original post, Technical Service “Red Flags” – GC, this post contains several additional Red Flags we look (email) and listen (phone) for in technical service.


Trying to set the carrier gas flow rate for a packed column without using a flow meter. You may want to review this previous post.

Verify your GC packed/micropacked column carrier gas flow to obtain reproducible results


When you have poor or no compound response for only the early eluting or later eluting compounds, but response for the other compounds are normal.

GC compound responses lower than expected? Maybe this will help.


Purchasing a compressed gas cylinder/tank regulator without knowing which CGA fitting is needed. Need some help in choosing the correct gas regulator?


Trying to cut capillary fused-silica or metal (MXT) tubing with scissors or wire cutters (or some similar household cutting tool).

Column Cutting, for making the Optimal Coupling: Do you use your Column-Scoring-Wafer the Right Way?


Using a splitless liner for split injections. While you may obtain acceptable results for sensitivity and reproducibility, obtaining a linear calibration curve may be difficult.

Liners Every Lab Should Own (in my opinion)


Trying to analyze Polywax® standards without using an on-column injection port, the proper simulated distillation GC column, and FID.



I hope you have found this second installment of “Red Flags” interesting and informative.  Thanks for reading.


All Red Flag posts:

Technical Service “Red Flags” – GC

More Technical Service “Red Flags” – GC

Even More Technical Service “Red Flags” – GC

Technical Service “Red Flags” – LC

More Technical Service “Red Flags” – LC



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