Gas Chromatography (GC): In this initial phase, the sample is vaporized and introduced into the GC column. Within the column, various compounds in the sample are separated based on their interaction with the column's stationary phase. This separation occurs because different compounds move through the column at different rates, leading to distinct retention times.

Flame Ionization Detector (FID): As the compounds exit the GC column, they pass through the Flame Ionization Detector. The FID burns the compounds, generating ions and electrons. The resulting electrical current is proportional to the concentration of the burned compound and is used to quantify the compounds in the sample.

Mass Spectrometry (MS): In the MS phase, the compounds are ionized, fragmented, and sorted based on their mass-to-charge ratio. This process creates a mass spectrum that serves as a chemical fingerprint of the compounds, allowing for their identification.

Data Analysis: The data generated by the FID and MS is processed by a computer, which combines the information to provide a comprehensive spectrum. This enables the identification and quantification of the compounds present in the sample.