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In this work the enantiomeric distribution of chiral coumarins (meranzin and epoxyaurapten), and furocoumarins (oxypeucedanin, byakangelicol, and epoxybergamottin) in different Citrusessential oils (lemon, lime, grapefruit, and bitter orange) was determined by means of a heart‐cutting multidimensional‐liquid chromatography (MD‐LC) system, equipped with a microsilica column in the first dimension in a combination to a cellulosic‐based chiral column used in the second dimension. The normal phase‐liquid chromatography‐liquid chromatography (NP‐LC‐LC) instrumentation was equipped with a photodiode array detector and a multiport valve as interface. For method optimization and the determination of absolute configuration, natural compounds were isolated and racemic mixture was synthesized. The NP‐LC‐LC/PDA (where PDA is photodiode array) method provided a good baseline separation of chiral coumarins (meranzin and epoxyaurapten) and furocoumarins (epoxybergamottin and byakangelicol) present in cold‐pressed Citrusessential oils without any sample pretreatment. Results obtained showed that for all the chiral compounds present in Citrusessential oils analyzed, there is always a clear prevalence of one of the two enantiomers, and do not appear influenced by the different geographical origin of the oils.

In 2009, a temporary crisis in the world production of acetonitrile caused the abnormal increase of the price of this substance, commonly used as a solvent and in high-pressure liquid chromatography (HPLC) separation as a mobile phase. For this reason, a new HPLC method was developed to analyze the oxygen heterocyclic components of Citrusoils, substituting acetonitrile with methanol. The new method described in this article was validated, new components were isolated and characterized by nuclear magnetic resonance (NMR), and others were synthesized, to obtain pure standards, not commercially available. The results are evaluated in comparison with methods previously developed. Seven genuine cold-pressed Citrusessential oils – lemon (C. limon(L.) Burm.), Key lime (C. aurantifolia(Christm.) Swing.) type B, bergamot (C. bergamia), grapefruit (C. paradisiMacf.), bitter orange (C. aurantiumL.), sweet orange (C. sinensis(L.) Osbeck) and mandarin (C. deliciosaTen.) – were analyzed under identical conditions. In conclusion, it was observed that the replacement of acetonitrile with methanol in the mobile phase and the increase of the column temperature (from 30 to 40°C) led to a better separation in terms of resolution and total analysis time. Limit of detection (LOD) and limit of quantification (LOQ) were comparable with methods previously developed with acetonitrile in the mobile phase.