Coupled liquid chromatography–gas chromatography for the rapid analysis of γ-oryzanol in rice lipids

An approach based on on-line coupled liquid chromatography–gas chromatography (LC–GC) was developed for the rapid analysis of γ-oryzanol in rice. Total lipids were extracted from rice and subjected to LC–GC without any prior purification. γ-Oryzanol was pre-separated by HPLC from rice lipids and transferred on-line to GC analysis in order to separate its major constituents, 24-methylenecycloartanyl ferulate, cycloartenyl ferulate, campesteryl ferulate, β-sitosteryl ferulate and campestanyl ferulate. The identities of the compounds were confirmed by off-line GC–MS analysis. Total γ-oryzanol content could be quantified by HPLC–UV detection and the distribution of γ-oryzanol constituents could be determined by on-line coupled GC analysis. The proposed methodology paves the way for high-throughput investigations providing information on natural variations in γ-oryzanol content and its composition in different rice varieties.