(+)-Limonene can also be extracted from the zest by Soxhlet extraction. A fiber thimble is filled with zest and isopropyl acetate is used as the extraction solvent.
The extracts from both isolation methods can be analyzed by GC to determine the composition of the volatile fraction as well as the % limonene yield from the zest. In pure form, limonene is a colorless liquid that boils at 173°C and has a sweet, orange odor.