Scope of GC — Which statement best reflects what gas chromatography can analyze (assuming analytes can be volatilized or appropriately derivatized without decomposition)?

Introduction / Context:
GC separates compounds in the gas phase. However, many practical samples are liquids or solids initially. The key is whether analytes can be vaporized (or chemically derivatized to become volatile) without decomposing, allowing GC analysis across diverse matrices.

Given Data / Assumptions:

• Analytes must be volatilizable and thermally stable under GC conditions.
• Derivatization (e.g., silylation, acylation) can increase volatility/thermal stability.
• Sample introduction methods include headspace, split/splitless liquid injection, SPME, and pyrolysis GC for certain solids.

Concept / Approach:
GC can analyze gases directly, solutions through liquid injection (after dilution or cleanup), and solids if they are dissolved, derivatized, extracted to the vapor phase (headspace/SPME), or, in specific cases, pyrolyzed. The broad scope is captured by acknowledging that the analyte must ultimately enter the column in the gas phase.

Step-by-Step Solution:

Verification / Alternative check:
Standard methods (e.g., residual solvents by headspace, pesticides by GC-MS after derivatization) illustrate GC utility for many matrices beyond gases alone.

Why Other Options Are Wrong:

• “Gases only” or “solids only” ignore common practice.
• “All of the above” would include mutually exclusive or incorrect constraints.
• “Aqueous solutions only” is false; nonaqueous matrices are routine in GC.

Common Pitfalls:
Forgetting thermal stability and volatility requirements; not all compounds are GC-amenable without derivatization.

Final Answer:
Gas chromatography is used to analyze gases, solutions, and solids (after volatilization/derivatization as needed).