Retention indices for naturally-occurring chiral and achiral compounds on common gas chromatography chiral stationary phases

Alavez-Rosas, David; Nguyen, Linh M.N.; Keefover‐Ring, Ken

doi:10.1016/j.rechem.2022.100659

Cited by 6 publications

(4 citation statements)

References 53 publications

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“…A summary of all 114 peaks initially identified in the TTO library ( n = 88) and oxidized TTO samples ( n = 12) is provided in Supporting Information Table S6. The peaks were then further identified by comparison to analytical standards, mass spectra in the NIST 17.0 MS library, SpectraBase, and PubChem, published RI on both chiral β-cyclodextrin and nonpolar columns ,,− and also considering the concentration and frequency of detection in unoxidized and oxidized TTO (Supporting Information Table S7). Twenty-five peaks were matched to analytical standards, 28 peaks were identified using both mass spectra and RI data, 14 peaks were identified by either RI or mass spectra data, 31 peaks were not identified, and 7 peaks were not considered further due to the low frequency of detection above 0.01% (Supporting Information Table S6).…”

Section: Resultsmentioning

confidence: 99%

“…Constituent identification was based on comparison of retention time to selected authentic standards (Supporting Information Table S1) and comparison of the spectra with mass spectral databases (NIST 17) using a probability-based matching algorithm. Additional identification was undertaken for TTO components previously reported, particularly considering relative retention indices (RIs) reported for chiral β-cyclodextrin and nonpolar columns. ,,− RIs were determined by comparing the retention time of identified components with the retention time of nearby n -alkanes in diesel fuel, using the generalized linear equation developed for temperature-programmed GC . In addition to measuring RI on the β-cyclodextrin column used in the reported e GC–MS method, RIs were also determined on a nonpolar HP-5MS column with the same parameters as the e GC–MS method except for a different He carrier gas flow (1.1 mL/min) and temperature program (Supporting Information Table S4).…”

Section: Methodsmentioning

confidence: 99%

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Comparison of Approaches for Authentication of Commercial Terpinen-4-ol-type Tea Tree Oils Using Chiral GC/MS

Linge,

Cooper,

Downey

2024

J. Agric. Food Chem.

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A global demand for tea tree oil (TTO) has resulted in increased adulteration in commercial products. In this study, we use a novel enantiomeric gas chromatography mass spectrometry method for chiral analysis of key terpenes ((±)-terpinen-4-ol, (±)-α-terpineol, and (±)-limonene) and quantification of components present at >0.01% to test different methods of identifying adulterated TTO. Data from authentic Australian (n = 88) and oxidized (n = 12) TTO samples of known provenance were consistent with recommended ranges in ISO 4730:2017 and previously published enantiomeric ratios, with p-cymene identified as the major marker of TTO oxidation. The 15 ISO 4730:2017 constituents comprised between 84.5 and 89.8% of the total ion chromatogram (TIC) peak area. An additional 53 peaks were detected in all samples (7.3−11.0% of TIC peak area), while an additional 43 peaks were detected in between 0 and 99% (0.15−2.0% of the TIC peak area). Analysis of nine commercial samples demonstrated that comparison to the ISO 4730:2017 standard does not always identify adulterated TTO samples. While statistical analysis of minor components in TTO did identify two commercial samples that differed from authentic TTO, the (+)-enantiomer percentages for limonene, terpinen-4-ol, and α-terpineol provided clearer evidence that these samples were adulterated. Thus, straightforward identification of unadulterated and unoxidized TTO could be based on analysis of appropriate enantiomeric ratios and quantitation of the p-cymene percentage.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Comparison of Approaches for Authentication of Commercial Terpinen-4-ol-type Tea Tree Oils Using Chiral GC/MS

Linge,

Cooper,

Downey

2024

J. Agric. Food Chem.

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“…However, validation and spiking experiments showed that the analytes were still quantifiable in a repeatable manner [ 31 ]. The calculated RI values are presented in Table 2 ; however, due to the scarcity of literature RI values for natural products analysed on chiral columns, no literature comparison could be conducted [ 33 ]. The bias, RSD R and RSD T did not exceed ± 15% for QC high , QC med and QC low (See Table 2 ).…”

Section: Resultsmentioning

confidence: 99%

Determination of Major, Minor and Chiral Components as Quality and Authenticity Markers of Rosa damascena Oil by GC-FID

Raeber

Favrod

2023

Plants

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Rose oil is traditionally produced by the water distillation of Rosa damascena and is of high economic value due to the low essential oil yield. It is therefore a common target for adulteration, which can cause harm to consumers. Current standards for authenticity control only consider the analysis of major components and overlook minor quality markers as well as the enantiomeric ratio of terpenes, which have proven useful in originality determination. The aim of this study was the development of two analytical GC-FID methods for the analysis of 21 and 29 rose oil analytes including major, minor and chiral components on a DB-wax and BGB 178 30% CD (chiral) capillary column, respectively. The total run time for both methods was within 60 min. For all target analytes, the % bias at the lower and upper calibration range varied from −7.8 to 13.2% and −13.1 to 5.2% analysed on the DB-wax column and 0.5 to 13.3% and −6.9 to 7.0% analysed on the chiral column. The chiral analysis successfully separated the enantiomers (+/−)-camphene, (+/−)-rose oxide, (+/−)-linalool, (+/−)-citronellol and (+/−)-citronellyl acetate, as well as the diastereomers of citral and β-damascenone. Both methods were applied to the analysis of 10 authentic rose oil samples and the enantiomeric/diastereomeric ratios, as well as the content of major and minor components, were determined. The identity of the analysed components in the authentic samples was further confirmed by GC-MS.

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“…The identification of enantiomers was performed by simultaneous analysis of the analytical standards and in reference to Alvarez-Rosas et al (2022) [10] study. The quantification was based on the peak area normalization performed against the internal standard peak area.…”

Section: Gc-ms Analysismentioning

confidence: 99%

Chemistry behind Quality—Emission of Volatile Enantiomers from Mentha spp. Plant Tissue in Relationship to Odor Sensory Quality

Łyczko

Kiełtyka-Dadasiewicz

Issa‐Issa

et al. 2023

Foods

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The quality of food, considering increasing consumer demands and competition among producers, is a highly important issue. Quality concerns are also applicable to the odor quality of herbs and spices (HSs). Meanwhile, HSs commonly are graded based on their essential oils (EOs) content and analysis; but does the instrumental analysis really provide general information about the HSs sensory quality? Three chemotypes of Mentha spp. were used in the present study. From samples diversified by convective drying at different temperatures, EOs were hydrodistillated and analyzed by enantioselective GC-MS; moreover, the source plant material’s volatile profile was analyzed by the HS-SPME technique. The instrumental analysis was confronted with the results of the sensory panel. Changes in enantiomeric composition were observed during the drying process, although no clear correlations or trends could be found for individual chiral components. Furthermore, even with significant differences in particular volatiles’ contribution to plants’ EOs and their volatile profiles, judges were not able to match the sample EOs and plant samples with sufficient effectiveness (~40%). Based on those results, we suggest that volatile enantiomeric distribution does not have an actual influence on odor quality and that the sensory analysis should not be replaced with instrumental analysis, which cannot predict general sensory quality.

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Retention indices for naturally-occurring chiral and achiral compounds on common gas chromatography chiral stationary phases

Cited by 6 publications

References 53 publications

Comparison of Approaches for Authentication of Commercial Terpinen-4-ol-type Tea Tree Oils Using Chiral GC/MS

Comparison of Approaches for Authentication of Commercial Terpinen-4-ol-type Tea Tree Oils Using Chiral GC/MS

Determination of Major, Minor and Chiral Components as Quality and Authenticity Markers of Rosa damascena Oil by GC-FID

Chemistry behind Quality—Emission of Volatile Enantiomers from Mentha spp. Plant Tissue in Relationship to Odor Sensory Quality

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