Question

A gas chromatogram of the organic components of a sample of beer using a column that separates compounds on the basis of their relative boiling points provides a GC trace with several peaks. Two of the smaller peaks, with retention times of 9.56 and 16.23 minutes, are believed to be ethyl acetate and ethyl butyrate, respectively.

a. From the above information, which component of the sample, ethyl acetate or ethyl butyrate, elutes faster? What are the reported boiling points of these two substances?

b. What GC experiment(s) could you perform to confirm the identity of the peaks at 9.56 and 16.23 minutes?

c. Suggest two ways in which you could adjust the conditions of the experiment so as to reduce the retention time for all components in the sample.

Answer 1

Solutions:-

a. From the above information, which component of the sample, ethyl acetate or ethyl butyrate, elutes faster? What are the reported boiling points of these two substances?

Solution :- Retention time of the ethyl acetate is less than the retention time of the ethyl butyrate therefore the ethyl acetate will elutesfaster.

Reported boiling points are as follows

Ethyl acetate = 77.1 C

Ethyl butyrate = 120 C

b. What GC experiment(s) could you perform to confirm the identity of the peaks at 9.56 and 16.23 minutes?

Solution :- GC/MS spectroscopy can be used to confirm the identity of the peaks at 9.56 and 16.23 minutes

c. Suggest two ways in which you could adjust the conditions of the experiment so as to reduce the retention time for all components in the sample.

Solution :- The eluate (solvent ) proportion can be altered to change the retention time of the each component of the mixture.

Also increasing the flow rate of the eluate can decrease the retention time of the each components of the mixture.