Gas chromatography-mass spectrometry is used to determine which category of compounds in a sample?

• A. Metals
• B. Inorganic compounds
• C. Organic compounds
• D. Elements

Answer: (C)

Gas chromatography-mass spectrometry excels at separating and identifying organic compounds in a mixture. The gas chromatography stage volatilizes the sample and separates components based on how they interact with the column, which works well for organic molecules that can be vaporized without decomposing. After separation, mass spectrometry analyzes each component by ionizing it and measuring the mass-to-charge ratios of the fragments. The resulting mass spectrum provides molecular weight information and a fingerprint pattern that helps confirm the identity of the compound. This combination is especially powerful for organic compounds, including solvents, pesticides, fragrances, drugs, and environmental organics. Metals and many inorganic compounds either do not volatilize under GC conditions or require different techniques (such as ICP-MS or AAS) to measure them, so GC-MS is not typically used to determine inorganic compounds or elements.