Question

7. What is the effect of the following on retention time seen in the GC? a. Increase in flow rate of carrier gas Increase in the temperature of the column b. c. Increasing the polarity of the column

Answer 1

a) In gas chromatography retention time will get reduced if we  increase the flow rate of carrier gas. because component in the mixture have lesser time to interact with the stationary phase and component will send forth through the column. this ultimately results in poor separation of the components.

b) temperature plays a major role in separating components by gas chromatography method. extremely high column temperature will reduce the retention time and component will not get sufficient time to get interact with the stationary phase and hence leads to poor separation of components in the mixture and reduced retention time.

c) Increasing the polarity of the stationary phase will increase the retention time for the reason that polar components will interacts firmly with polar stationary phase and it stays some time in column compared to lesser polar components in the mixture and hence time taking for polar components to push through the column will be higher and this leads to increase in retention time. this will give good separation of the components.