UPLC method for the determination of limonene in sweet orange (Citrus sinensis) oil

The citrus-derived bioactive monoterpene limonene is an important industrial commodity and fragrance constituent that is usually quantified by GC. A reversed-phase isocratic C-18 UPLC method using a superficially porous stationary phase, and monitored by photodiode-array detector, has been developed for determining the limonene content of sweet orange (Citrus sinensis) oil. The method is fast, with a cycle time of 1.2 minutes, linear, precise, accurate, specific, according to USP system suitability parameters, and stability-indicating. The method could be useful in its present form for limonene processing, or modified for research on more polar compounds of the terpenome. The stability experiment showed that limonene is degraded by heat over time. Photodiode-array detection facilitated the classification of minor components and impurities of the essential oil, such as β-myrcene.

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