Overcoming Low-response in GC-FID Analysis
Wednesday, March 10, 2021: 9:10 AM - 9:30 AM
What do aldehydes, chlorofluorocarbons and silylated compounds have in common? They are a pain to analyze via GC-FID! The flame ionization detector (FID) is the most widely used detector because of its simplicity, large linear range (from 0.1 ppb to 100%), and general response to carbon. The response of the FID is very uniform for saturated hydrocarbons because these compounds react in H2/air flames to form similar numbers of CHO+ ions. Problems arise when compounds containing lots of oxygen, chlorine, fluorine, silicon, and other heteroatoms enter the flame because they lower the propensity to form CHO+ ions, resulting in a lower (or no) response. Here, we demonstrate that we can circumvent this loss in sensitivity for most compounds by converting to methane first in a pre-flame reactor. We can improve sensitivity even further to part-per-trillion levels with large volume injection techniques or pre-column concentration. With these advances it is possible to use the GC-FID for (nearly) all carbon containing compounds with excellent sensitivity, linearity, accuracy, and reproducibility.
Keywords: Please select up to 4 keywords ONLY:
Chromatography - Other,Instrumentation,Specialty Gas Analysis,Green Chemistry