Question

         Gas chromatography questions

1. why is GC separation more efficient than a fractional distillation?

2. what characteristics must the liquid stationary phase have?

3. how do the flow rate of the carrier gad and the column temperature affect the retention time of a compound on a GC column?

4. Describe a method for identifying a compound using GC analysis

Answer 1

1. why is GC separation more efficient than a fractional distillation?

Solution :- In the GC we can increase the number of the theoretical plates which can increases the separation of the mixture component which cannot be done in the fractional distillation therefore GC is more efficient than the fractional distillation.

2. what characteristics must the liquid stationary phase have?

Solution :- A liquid stationary phase must be low volatile. It should be thermally stable.

The liquid stationary phase should chemically inert so that it cannot react with the mixture components. Liquid stationary phase should have good interactions with the solute so it can achieve the highest separation of the components of the mixture.

3. how do the flow rate of the carrier gad and the column temperature affect the retention time of a compound on a GC column?

Solution :- When we increase the temperature of the column then it increases the separation by decreasing the retention time of the solute.

When the flow rate is high then it decreases the run time of the GC.

4. Describe a method for identifying a compound using GC analysis

Solution :- A GC analyzer compares the components of the mixture with the standard compounds for their identification. In the advance GC-MS analyzer the fragmentation of the compounds in the mass spectrum used to analyze and identify the compounds.