A Gas Chromatography-Flame Ionization Detector (GC-FID) system is a widely used analytical instrument for separating, identifying, and quantifying volatile and semi-volatile organic compounds, with particular effectiveness for hydrocarbons. It is a workhorse in many analytical laboratories due to its reliability and broad applicability. In a GC-FID system, a sample is first injected into a heated inlet, where it is vaporized. The vaporized components are then carried through a chromatographic column by an inert carrier gas (e.g., helium, nitrogen, or hydrogen). The column separates the compounds based on their differing affinities for the stationary phase and their volatility. As the separated compounds elute from the column, they enter the Flame Ionization Detector (FID). Within the FID, the organic compounds are combusted in a hydrogen-air flame, which generates ions. These ions produce a measurable electric current that is directly proportional to the mass flow rate of carbon atoms, allowing for highly sensitive and quantitative detection. The FID is known for its high sensitivity to most organic hydrocarbons and offers a wide linear dynamic range, typically spanning 10⁷ g/s. GC-FID is extensively applied across numerous industries and research areas. It is a primary tool in the petrochemical industry for analyzing the composition of fuels, natural gas, and various hydrocarbon mixtures. In environmental analysis, it is used for monitoring air quality, detecting volatile organic compounds (VOCs), and analyzing contaminants in water and soil. Food testing laboratories employ GC-FID for determining fatty acid profiles, analyzing flavors, and detecting certain food contaminants. In pharmaceutical testing, it is used to identify and quantify residual solvents and other volatile impurities. GC-FID systems are generally considered cost-effective, require relatively low maintenance, and are known for their rugged construction. They can be configured with various types of GC columns to optimize separation for different sample types. The accompanying software facilitates data acquisition, chromatogram interpretation, and the generation of calibration curves for accurate quantification, making it a versatile and dependable analytical technique.