Analysis of essential oils and fatty acids from Platycodi Radix using chemometric methods and retention indices.

The chemical composition of the essential oils and fatty acids among nine groups of Platycodi Radix in China was analyzed by gas chromatography-mass spectrometry. Complicated components were resolved using chemometric methods. Simultaneously, the various features among heuristic evolving latent projections, selective ion analysis and alternative moving window factor analysis were compared by using some experimental data. Temperature-programmed retention indices were applied in further identification of the chemical composition of the essential oils. The equivalent chain length, fraction chain length, and an established special retention indices library integrated with mass spectrometry were also applied to further identify the composition of fatty acids, including total fatty acids, esterified fatty acids and free fatty acids. A total of 121 different compounds accounting for 95.12-98.74% were identified among the essential oils. Chemical polymorphisms and variation existed in the essential oils of Platycodi Radix. Sixteen components were identified in fatty acids, and linoleic acid (18:2n-6c) and other unsaturated acid possess a characteristic majority.