Question

How can you improve the resolution between two closely spaced peaks in gas chromatography. Describe the process you would undertake to improve separation.

Answer 1

In general, a compound with lower boiling point will move faster in the GC column than a compound with a higher boiling point. Now, that is assuming that the interaction between these two solutes and the stationary phase are of nearly equal magnitudes (but that is an overstatement, many factors are still at play here). With that in mind, we can infer that changing the column temperature will have an effect on the rate of retention/elution. Increasing the column temperature will allow greater separation of two molecules with wide differences in boiling points.

Regarding the second parameter, increasing the gas flow rate will shorten the amount of time these solutes will stay in the column, i.e. your run time will decrease.

Then, if you attempt several tweaks for these two parameters (column temperature and flow rate), you may be able to separate very close (or overlapping) peaks and achieve them in a relatively short run time.

Second option is use a narrower column, or a longer column, or try different stationary phases.