On-column injector

[vanja13]

I have a capillary gc method for fatty amines determination for GC with an on-column injector (30°C).Is it possibble to predict what will happen if a normaL GC injector is used with the same all the other parameters and the same column?

[Victor]

Amines can be difficult samples to analyse by GC because they may adsorb reversibly or irreversibly to the column surface, or to any part of the GC e.g. the injection liner in a split/splitless injector.

Although on-column injectors can have their own problems, one problem that is eliminated is the adsorption of solute in the injector iteself, becuase if the conditions are set correctly, the sample should only contact the syringe needle before it enters the column. The vaporisation step in the liner is eliminated. Thus it is possible that the method was designed for use with on-column injection specifically for this reason, and that adsorption problems could be encountered if using a split/splitless injector. The best way to check is by performing the analysis on your instrument and comparing with the results claimed for the on-column method. It may be that you get no problems at all.