Synthesis of Deuterated Volatile Lipid Degradation Products To Be Used as Internal Standards in Isotope Dilution Assays. 1. Aldehydes

Lin, Jianming; Welti, Dieter H.; Vera, Francia Arce; Fay, Laurent B.; Blank, Imre

doi:10.1021/jf9902088

Cited by 41 publications

(66 citation statements)

References 25 publications

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“…Deuteration of commercially available 2-octyn-1-ol (2) resulted in [2,3-2 H 2 ]-(E)-2-octen-1-ol (d-3) in 75% yields. As recently shown, reduction of α-acetylenic alcohols with LiAl 2 H 4 leads preferably to trans-configured olefinic alcohols (22). The high stereospecificity was explained by geometrical constraints of cyclic intermediate structures.…”

Section: Preparation and Characterization Of [45-2 H 2 ]-Trans-45-ementioning

confidence: 73%

“…All shifts are cited in ppm from the internal tetramethylsilane (TMS) standard. Where appropriate, proton nuclear Overhauser effect (NOE) difference spectra, distortionless enhancement by polarization transfer (DEPT) and/or fully proton-coupled spectra, and two-dimensional homonuclear and heteronuclear correlation spectra (COSY and HETCOR, respectively) were acquired as described earlier (22).…”

Section: Methodsmentioning

confidence: 99%

“…Commercially available 2-octyn-1-ol (2) was used as starting material to prepare [2,3-2 H 2 ]-(E)-2-octen-1-ol (d-3) by reduction with LiAl 2 H 4 followed by deuterolysis (22). Oxidation of d-3 with MnO 2 according to (23) (24).…”

Section: Synthesis Of [45-2 H 2 ]-Trans-45-epoxy-(e)-2-decenal (D-1)mentioning

confidence: 99%

“…Small signals for the residual nondeuterated 2-C and 3-C in about 1:3 ratio were observed at 132.89 (d) and 159.04 ppm (d), respectively. The NMR assignments above were based on our data of undeuterated (E)-2-octenal (not cited here), the assignments of which were in turn derived from those of natural abundance and 2,3-deuterated (E)-2-nonenal (22).…”

Section: Synthesis Of [45-2 H 2 ]-Trans-45-epoxy-(e)-2-decenal (D-1)mentioning

confidence: 99%

“…Proton 22.52, t 22.52, t 10-CH 3 13.96, q 13.96, q including proton NOE difference spectra, COSY, and HETCOR for direct carbon-proton couplings. The structure of 1 could be confirmed, as shown in Tables 2 and 3 The NMR spectra also indicated the presence of about 7% of an isomer.…”

Section: H Nmr Data Of Trans-45-epoxy-(e)-2-decenal (1) and [45-2 Hmentioning

confidence: 99%

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Synthesis of trans‐4,5‐epoxy‐(E)‐2‐decenal and its deuterated analog used for the development of a sensitive and selective quantification method based on isotope dilution assay with negative chemical ionization

Lin

Fay

Welti

et al. 1999

Lipids

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The volatile compound trans-4,5-epoxy-(E)-2-decenal (1) was synthesized in two steps with good overall yields. The newly developed method is based on trans-epoxidation of (E)-2-octenal with alkaline hydrogen peroxide followed by a Wittig-type chain elongation with the ylide formylmethylene triphenylphosphorane. For the synthesis of [4,5-2H2]-trans-4,5-epoxy-(E)-2-decenal (d-1), [2,3-2H2]-(E)-2-octenal was prepared by reduction of 2-octyn-1-ol with lithium aluminum deuteride and subsequent oxidation of [2,3-2H2]-(E)-2-octen-1-ol with manganese oxide. Compound d1 was used as internal standard for the quantification of 1 by isotope dilution assay. Among various mass spectrometry (MS) ionization techniques tested, negative chemical ionization with ammonia as reagent gas gave best results with respect to both sensitivity and selectivity. The detection limit was found to be at about 1 pg of the analyte introduced into the gas chromatography-MS system.

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Section: Preparation and Characterization Of [45-2 H 2 ]-Trans-45-ementioning

confidence: 73%

Section: Methodsmentioning

confidence: 99%

Section: Synthesis Of [45-2 H 2 ]-Trans-45-epoxy-(e)-2-decenal (D-1)mentioning

confidence: 99%

Section: Synthesis Of [45-2 H 2 ]-Trans-45-epoxy-(e)-2-decenal (D-1)mentioning

confidence: 99%

Section: H Nmr Data Of Trans-45-epoxy-(e)-2-decenal (1) and [45-2 Hmentioning

confidence: 99%

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Synthesis of trans‐4,5‐epoxy‐(E)‐2‐decenal and its deuterated analog used for the development of a sensitive and selective quantification method based on isotope dilution assay with negative chemical ionization

Lin

Fay

Welti

et al. 1999

Lipids

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Identification and Quantitation of Aroma Compounds

Milo

2001

Current Protocols in Food Analytical Chemistry

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Identification and Quantitation of Aroma Compounds After isolation of the volatiles using different extraction and concentration procedures (UNIT G1.2) the samples are injected into a gas chromatograph (GC) for separation of individual compounds. Identification is based on their Kovats retention indices on two columns of different polarity, as well as comparison with mass spectroscopy (MS) spectra of the corresponding reference compounds. Quantification is then performed using one or several compounds as internal standards, which naturally do not occur in the sample, added to the sample before extraction, if possible. Depending on the type and availability of these standards, quantitation is preferably performed by gas chromatography-flame ionization detection (GC-FID; see Basic Protocol) or gas chromatography-mass spectrometry (GC-MS) using isotope dilution assays (IDAs; see Alternate Protocol). Other methods for quantification based on external standards are less accurate, and those based on multiple standard addition at different concentrations are only rarely needed. BASIC PROTOCOL IDENTIFICATION (GC-FID; GC-MS) AND QUANTIFICATION OF VOLATILES (GC-FID) Volatiles are separated by GC and their elution time monitored relative to a series of n-alkanes that are injected under identical conditions. The most common GC detector is the flame ionization detector (FID), which is also widely used in flavor research. The detector responds to all organic compounds that burn or ionize in its flame, and is characterized by a large dynamic range (Buffington and Wilson, 1987). The temperature program chosen for the separation of compounds is dominated by mutually exclusive parameters like speed, resolution, and capacity. For separation of highly volatile odorants, sub-ambient GC-start temperatures are recommended. The steps described in this unit for the identification are limited to compounds that are listed in common data banks. Analytical methods to identify a compound that has never been reported before are not discussed, and the reader is referred to experts in natural products chemistry. Unambiguous identification requires that an authentic standard has been shown to have the same chromatographic, spectral, and olfactory properties. Anything less is tentative; however, like other problems in analytical biochemistry the biological activity (i.e., olfaction) is a powerful indication of the identity of a standard and an analyte especially when combined with chromatography. Materials Aroma samples Solution of 10 to 100 µg/ml n-alkanes (C5 to C25) in diethylether (freshly distilled) Reference compound Internal standard compound Gas chromatograph with FID and sniffing port (Hewlett Packard) DB5 and DBWAX capillary columns (e.g., 30-m × 0.25-mm; f = 0.25 µm; J&W Scientific) Gas chromatograph with MS detector (with EI mode and optional CI mode; Hewlett Packard) Additional reagents and equipment for extraction methods (see UNIT G1.2) Contributed by Christian Milo

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Nuclear magnetic resonance analysis of extra virgin olive oil: classification through secoiridoids

Tsiafoulis,

Liaggou,

Garoufis

et al. 2023

J Sci Food Agric

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BACKGROUNDExtra virgin olive oil (EVOO), a natural product with a multidisciplinary role, has been and is continuing to be studied from several points of view. Among them, its chemical analysis is of major importance and several methods have been used. Nuclear magnetic resonance (NMR) spectroscopy has inherent advantages, among them monitoring the chemical constituents without the need for a separation technique and without, for instance, possible carry‐over effects. Additionally, several magnetic resonance spectroscopic techniques can provide a novel powered insight into the nature and properties of a sample under study. Moreover, ‐omics procedure can reveal new information and can lead to the classification of populations under study. The main objective of the present work was the possible classification of the EVOO samples based on their aldehyde content using a proposed unreferenced 1H‐NMR spectroscopic quantification method combined with a metabolomic approach. Moreover, the study of the impact of such elevated aldehyde content on several spectra regions of importance in the proton NMR spectra led to the proposal of a possible new isomer indicator.RESULTSUnivariate analysis of 12 EVOO samples showed that oleacein, oleocanthal, elenolic acid, hydroxytyrosol/hydroxytyrosol derivatives and tyrosol/tyrosol derivatives strongly differentiated two classes of EVOO: OEH (for high aldehyde EVOO content) and OE (for non‐high aldehyde content). Moreover, we pointed out the 'impact' of such elevated secoiridoid and derivatives content, through their moieties' units, on a range of several resonances of the 1H‐NMR spectrum. The metabolomic approach demonstrated the classification of EVOO samples based on their secoiridoid and derivatives content. Multivariate analysis showed a strong influence on the discrimination of the EVOO classes based on the protons resonating at the aldehyde region of the 1H‐NMR spectrum; the aldehyde protons corresponding to 5S,4R‐ligstrodial and 5S,4R‐oleuropeindial, oleacein, oleocanthal, elenolic acid, p‐HPEA‐EA, 3,4‐DHPEA‐EA, 5S,4R‐ and 5S,4S‐ligstrodial and the proton corresponding to a new compound were reported for the first time. This isomer compound, reported for the first time, could serve as a possible indicator for EVOO classification.CONCLUSIONSAn unreferenced quantification method was proposed and EVOO samples were classified into two classes: OEH and OE, according to their aldehyde content, gaining thus probably higher nutrient and possible pharmacological value. Moreover, we point out the 'impact' of such elevated aldehyde content on several spectral regions of the 1H spectrum. Finally, a new compound was detected in the OEH samples and is reported for the first time. This compound could possibly be an indicator. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

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Synthesis of Deuterated Volatile Lipid Degradation Products To Be Used as Internal Standards in Isotope Dilution Assays. 1. Aldehydes

Cited by 41 publications

References 25 publications

Synthesis of trans‐4,5‐epoxy‐(E)‐2‐decenal and its deuterated analog used for the development of a sensitive and selective quantification method based on isotope dilution assay with negative chemical ionization

Synthesis of trans‐4,5‐epoxy‐(E)‐2‐decenal and its deuterated analog used for the development of a sensitive and selective quantification method based on isotope dilution assay with negative chemical ionization

Identification and Quantitation of Aroma Compounds

Nuclear magnetic resonance analysis of extra virgin olive oil: classification through secoiridoids

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