quick question

[samuch]

a question for gas chromatography:

The organic compounds dimethyl ether (CH3OCH3) and ethanol
(CH3CH2OH) have the same molecular formula, C2H6O, and
the same molar mass; however they have different structural
formulas.
A sample containing both ethanol and dimethyl ether is
analysed by GLC using a fl ame ionisation detector.

a) Will the two compounds produce peaks with the same
retention time? Explain your answer.

b) If the sample has the same concentration of both
chemicals, will the peaks produced have the same area?
Explain your answer.

____________________________________________________

so can someone please explain why the answers to these are both no and why?
thank youuuuu

[superflya]

same molecular formula but the bonding isnt the same, so u cant have the same Rt values as the affinity of both the substances to the stationary phase arent equal.

[kyzoo]

a.) The two compounds have different functional groups, which means they have different chemical properties. So they will have differing affinities for the stationary and mobile phase, hence the two compounds won't have the same retention times.

b.) For a flame ionisation detector, the area under the peak depends on the sensitivity of the detector to the compound. Each compound has different sensitivities as they have different chemical properties (as explained in the previous question). Hence they will not produce the same peak areas despite being of the same concentration.