Question

The stationary phase of the GC columns in the organic chemistry labs is silicone oil, and so the boiling points of the sample compounds determine the order of elution. The highest boiling species is the last to elute from the column. In the analysis of your distillation fractions by GC, the peak that elutes firstfrom the column will correspond to which component of the mixture?

Answer 1

The Silicone oil which is used as a stationary phase in the GC column, separates the compounds based on their boiling points. The lowest boiling point compound will elute first from the column and the compound with highest boiling point will elute last from the column. The close boiling point compound can also be separated by appropriate temperature programming of the GC column.

Therefore in the present analysis of the distillation fractions, the peak which elutes first from the column has the lowest boiling point.