Antonella Cotroneo

Multidimensional capillary GC-GC for the analysis of real complex samples. Part IV. Enantiomeric distribution of monoterpene hydrocarbons and monoterpene alcohols of lemon oils

This paper describes a fully automated, multidimensional, double-oven GC-GC system, developed in our laboratory. The system is based on the use of mechanical valves which allow the multitransfer of different fractions during the same GC analysis and the use of the two GC independently when the multitransfer options is not used. Pneumatic and electronic circuits permit maintenance of constant retention times in the pre-column, even for the components eluted after numerous transfers. The system has been used for the determination of the enantiomeric distribution of β-pinene, sabinene, limonene, linalol, terpinen-4-ol, and α-terpineol in lemon oils. The results obtained allowed the characterization of cold-pressed lemon oils.

On the Genuineness of Citrus Essential Oils. Part XLIII. The Composition of the Volatile Fraction of Italian Sweet Orange Oils (Citrus sinensis (L.) Osbeck)

ABSTRACT The composition of the volatile fraction of Italian sweet orange oil obtained from blond and blood pulp fruits has been studied by GC and GC/MS. The study has been carried out on 190 genuine oils obtained by “Pelatrice” and “FMC in-line” industrial processing during the 1991–92 season. More than 55 components have been identified in the oil, with limonene (ca. 95%) as the main component. Because of the relatively high percentage of octanal and decanal found in the oil, the carbonyl compounds are the most important components of the oxygenated fraction. The results obtained establish that the quantitative composition of sweet orange oil shows peculiar variations in many components during the season and greatly depends on the isolation procedure and the kind of fruit processed. Oil produced by the “Pelatrice” method has a lower monoterpene content and a higher aldehyde and alcohol content than the oil produced during the same time period by “FMC” process. Also, blood oils generally show a higher mo...

Sicilian lemon oil: Composition of volatile and oxygen heterocyclic fractions and enantiomeric distribution of volatile components

A total of 92 samples of Sicilian lemon oils (Citrus limon (L.) Burm. f.) produced from September 2008 to June 2009, industrially cold-pressed by different extraction techniques (Brown Oil Extractor and Food Machinery Corporation), were analyzed by GC-flame ionization detector (FID) and GC/MS-LRI to investigate the volatile fraction; by RP-HPLC/PDA to determine the non-volatile components and by enantio-GC-FID to determine the enantiomeric ratios of 12 volatile components. This study provides a detailed investigation on the composition of Sicilian lemon essential oils industrially produced during a productive season, with the aim to recognize quality parameters for the characterization of this product. The results obtained are discussed to evaluate seasonal variation, influence of the extraction techniques, and are compared with those obtained for samples produced during different seasons.

Characterization of cold-pressed and processed bergamot oils by using GC-FID, GC-MS, GC-C-IRMS, enantio-GC, MDGC, HPLC and HPLC-MS-IT-TOF

Numerous samples of Italian cold-pressed bergamot oils, representative of the industrial production of the last three seasons (2008/09, 2009/10 and 2010/11), as well as several samples of bergapten-free, concentrated and recovered oils, have been extensively investigated in the present study. The samples were analyzed to determine the composition of the volatile fraction, the oxygen heterocyclic compounds, the enantiomeric distribution of twelve volatile components and the isotopic ratios of selected volatiles. Differences from previous studies emerged. The recent improvement in cultural practices is confirmed by the increase of linalool and linalyl acetate, indicative of better quality of the essential oils. The seasonal variation of the enantiomeric excess of α-terpineol, characteristic of cold-pressed bergamot oils, is confirmed. Some oxygen heterocyclic compounds are here quantitatively determined for the first time. The presence of herniarin is confirmed in genuine samples through high-pressure liquid-chromatography–mass spectrometry–ion trap–time of flight (HPLC-MS-IT-TOF). The isotopic ratios herein reported, for all the samples analyzed, represent a useful tool for the evaluation of genuineness of cold-pressed and processed bergamot oils.

Gas chromatographic separation and chemometric analysis of mandarin essential oils

Abstract Capillary gas chromatography with flame ionization detection was applied to the separation of components of mandarin essential oils. Fifty-nine genuine samples were considered over the period October 1982–January 1983. Essential oils were obtained from unripened green fruits and ripened red fruits, as well as from fruits at intermediate ripening. Thirty-four pure components were systematically identified, but only 13 were used as variables for the further characterization by a chemometric procedure. Principal component analysis was applied to the differentiation of samples with different maturation and obtained with different technologies.

Enantiomeric distribution of key volatile components in Citrus essential oils

Citrus as many other plants present characteristic distribution of some enantiomers, thus it is often possible to use this parameter for identification, characterization, genuineness, and pharmacological activity assessment. In particular, it is possible to reveal adulteration of different nature, such as addition of synthetic compounds, or natural components of different botanical origin, with drastic changes in the biological and olfactory properties. This study is focused on the evaluation of the enantiomeric excesses of numerous samples of different Citrus species: C. deliciosa Ten., C. limon (L.) Burm., C. bergamia, C. aurantifolia (Christm.) Swing., C. latifolia Tan., C. sinensis (L.) Osbeck, and C. aurantium L. The enantiomeric distribution is determined by direct esGC and, depending on the complexity of the essential oil, by MDGC with a chiral column in the second dimension. The research is focused on the determination of fourteen chiral components which present specific distribution in the essential oils investigated. Particular attention is given to the trend of the enantiomeric distribution during the productive season, so to identify useful parameters for quality assessment also in consideration of the wide range of variability often reported in literature. The components investigated were the following: α-thujene, α-pinene, camphene, β-pinene, sabinene, α-phellandrene, β-phellandrene, limonene, linalool, camphor, citronellal, linalyl acetate, terpinen-4-ol, α-terpineol. The use of MDGC allowed the separation of the enantiomers of camphor and citronellal, otherwise not separated by conventional esGC; however for the separation of the enantiomers of α-pinene it was preferable to use conventional esGC. The MDGC system allowed to determine the enantiomeric distribution of camphene, α- and β-phellandrene in lime essential oil for the first time. The results are discussed in function of seasonal variation and, when possible, in function of the extraction technology, with particular regards to lime oils.

Italian Citrus petitgrain oils. IV. Composition of lemon petitgrain oil

Abstract The composition of Italian industrial lemon petitgrain oil has been examined by HPLC-GC/MS (ITD), GC/MS (quadrupole) and GC using GC capillary SE-52 and Carbowax 20 M columns. A total of 66 compounds have been identified, which represent 98–99% of the whole oil. Among the oxygenated compounds identified, aldehydes were found in highest proportions. 1,8-Cineole, which is either absent or present only as trace in the other Citrus petitgrains, represented 1.1–2.1% of lemon petitgrain oil. Lemon petitgrain oil is more similar to lemon peel oil, than the other Citrus petitgrain oils to the correspondent peel oils.

On the Genuineness of Citrus Essential Oils. Part XLVIII. The Composition of Volatile Fraction of Some Varieties of Sweet Orange Oils

ABSTRACT The composition of the volatile fraction of 164 Italian sweet orange oils, laboratory-prepared from fruits of different cultivars, has been studied by GC and GC/MS. The following cultivars have been examined: Biondo comune, Navelina, Washington navel, Ovale, Valencia late (blond cultivars) Tarocco, Moro, Sanguinello (blood cultivars). The average composition of each of the cultivars is reported as is the standard deviation for each compound. As a result, the behavior of the classes of substances and of some of the components during the period analyzed are shown. Furthermore, the results are compared with those of previously analyzed commercial sweet orange oils.

On the genuineness of citrus essential oils. Part LVII. The composition of distilled lime oil

The composition of distilled lime oil has been investigated. The analytical techniques used to fractionate the oils and identify each component were: open column chromatography, gas chromatography, gas chromatography-mass spectrometry. Among the 113 compounds identified, 28 are reported to be present in distilled lime oil for the first time. The main differences between the cold-pressed and the distilled lime oil are also discussed.

Uruguayan Essential Oils. Part VII. Composition of Leaf Oil of Eugenia uruguayensis Camb. var. uruguayensis (Myrtaceae)

Abstract Eugenia uruguayensisleaf oil, obtained by hydrodistillation, was analyzed by GC and GC/MS. Sixty components were identified in the oil. The main components were limonene (17.6%), 1,8-cineole (17.0%), α-pinene (10.0%) and caryophyllene oxide (8.3%).