Home / Summaries / Advanced Biochemical Analysis of Food / gc-temperature-run

Chromatography - Gas Chromatography (GC)

Q: What is the most common GC detector?

FID (flame ionization detection): The signal is generated by electrons created when combusting the eluting analytes. It is general and very sensitive, but it does not give any clue on the identification of unknown compounds MS (mass spectrometry): The detector is a mass spectrometer. It is general, fairly sensitive and also allows to get information useful for the identification of the unknown peaks in the chromatograms.

4 important questions on Chromatography - Gas Chromatography (GC)

What are the 2 different elution modes?

Isothermal: temperature is kept constant during all the run, you use it if there is one temperature more or less oke for all your compounds, so similar volatilizes
Gradient: temperature is gradually increased during the run. If you have no idea what you are going to find.

What is the most common GC detector?

FID (flame ionization detection): The signal is generated by electrons created when combusting the eluting analytes. It is general and very sensitive, but it does not give any clue on the identification of unknown compounds
MS (mass spectrometry): The detector is a mass spectrometer. It is general, fairly sensitive and also allows to get information useful for the identification of the unknown peaks in the chromatograms.

How can you analyse AA with GC?

LC techniques usually more suitable, but they can be analysed by GC after derivatization, aimed at masking the amino and carboxy groups. Chiral separation then easily achievable on chiral GC column.

So see if it is a D or a L AA.

How can you analyse Fatty acid methyl esters (FAME) with a GC?

Analysis requires degradation/derivatization reaction of tryglycerides to trasform fatty acids contained in them in fatty acid methyl esters, volatile compounds.