Gas Chromatography

Question 1

Make a diagram illustratating instrumentation of GC

Answer 1

See diagram.

Question 2

Explain the process of sample separation in gas chromatography.

Answer 2

1. the sample (in either liquid or gaseous form) is injected into the system, where it is rapidly vaporized in a heating chamber.
2. The vaporized sample is then carried by an inert mobile phase (e.g., helium or nitrogen) into a column containing a stationary phase.
3. As the sample travels through the column, its components interact with the stationary phase to varying degrees, causing each to travel at different speeds.
4. Components that interact more strongly with the stationary phase take longer to pass through the column, while those with weaker interactions move faster.
5. A detector at the end of the column monitors the effluent, producing a chromatogram showing peaks that correspond to the separated components based on their retention times.

Question 3

Discuss the role of temperature programming in gas chromatography and its importance in the analysis of complex samples.

Answer 3

• Temperature programming involves gradually increasing the temperature of the column during a GC run. This is important for the separation of complex mixtures containing both low and high volatility components.
• At the start of the analysis, the temperature is kept low to allow good separation of low volatility (high boiling point) components. As the analysis progresses, the temperature is increased in a controlled manner, allowing higher volatility components to exit the column faster.
• Improves efficiency of seperation, reducing analysis time, ensuring sharper and better resolved chromatographic peaks.