Analysis of the monoenoic fatty acid distribution in hydrogenated vegetable oils by silver‐ion high‐performance liquid chromatography

Adlof, R. O.; Copes, L. C.; Emken, E. A.

doi:10.1007/bf02638858

Cited by 51 publications

(27 citation statements)

References 15 publications

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“…The Ag + -HPLC method, developed by Adlof et al [22] and refined and applied to CLA isomers by Sehat et al [19], was modified as follows: two analytical silver-impregnated HPLC columns were fitted in series (ChromSpher 5 Lipids, 4.6 mm i.d.6250 mm stainless steel; 5 lm particle size, Chrompack, Netherlands). The HPLC (Merck/Hitachi 655A-12 LC, L-5000 Controller) was equipped with a UV detector (Merck/Hitachi L 4 200 UV/VIS) and an operating system (Chromstar, version 3.20).…”

Section: + -Hplcmentioning

confidence: 99%

Enhanced Resolution of Conjugated Linoleic Acid Isomers by Tandem-Column Silver-Ion High Performance Liquid Chromatography

Rickert¹,

Steinhart²,

Fritsche

et al. 1999

J. High Resol. Chromatogr.

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A commercial mixture of conjugated linoleic acid (CLA) isomers, reportedly consisting of six components, was recently resolved into 12 peaks attributed to CLA isomers using silver‐ion high performance liquid chromatography (Ag+‐HPLC). In this study, the coupling of two analytical silver‐ion high performance liquid chromatography columns (tandem‐column Ag+‐HPLC) in series led to the enhanced resolution of CLA isomers. Many CLA isomers were baseline resolved and the pair 18 : 2 8,10 c/t and 18 : 2 7,9 c/t found in cheese products, was resolved for the first time. In this work, a similar commercial CLA mixture was separated into 16 peaks, while CLA isomers from cheese also gave rise to 16 peaks. As expected, the CLA isomers were separated into three geometric groups in the order trans,trans, cis/trans, and cis,cis. Semi‐preparative Ag+‐HPLC, followed by gas chromatography–mass spectroscopy of the dimethyloxazoline derivatives, was used to confirm the identity of the newly resolved positional CLA isomers. The double bond configuration of CLA isomers was established by gas chromatography–Fourier transform infrared spectroscopy. Two minor t,t CLA isomers found in cheese, presumably 18 : 2 t6t8 and 18 : 2 t13t15, were also separated. The CLA isomeric composition of 16 commercial cheese products was determined.

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Section: + -Hplcmentioning

confidence: 99%

Enhanced Resolution of Conjugated Linoleic Acid Isomers by Tandem-Column Silver-Ion High Performance Liquid Chromatography

Rickert¹,

Steinhart²,

Fritsche

et al. 1999

J. High Resol. Chromatogr.

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“…® column has, however, been used as a good alternative to Ag-TLC for preliminary isomer fractionation before GC analysis, and as a method for isolating most 18:1 positional isomers [70]. A collaborative study [86] showed that this methodology gives results that are as good, repeatable and reproducible as Ag-TLC as regards trans-18:1 fractionation prior to GC analysis.…”

Section: A Chromspher Lipidsmentioning

confidence: 99%

“…Using this column, procedures were developed to fractionate trans-and cis-monoenoic FAME by Ag-HPLC for further GC analyses of the two separate fractions [32,70]. This technique was used to determine the total trans-monoene content of PHVO and results were compared with data obtained by FTIR [32].…”

Section: Silver Nitrate Hplcmentioning

confidence: 99%

Analytical methods for determination of trans fatty acid content in food

Juanéda¹,

Ledoux

Sébédio

2007

Euro J Lipid Sci & Tech

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Adequate analytical tools are required for labelling food products for trans fatty acid (TFA) contents. The choice of the fatty acid (FA) derivatisation is a crucial step in obtaining good results, in particular with short-chain and conjugated FA. Several gas chromatographic and infrared spectrophometric methods have been developed for analysing TFA in foods, some of which have been validated as official methods after collaborative studies. Complete analysis of total FA often requires the use of complementary high-performance liquid chromatography methods. This paper reviews the analytical methods developed for identifying and quantifying TFA in foods and presents the official methods of analysis. Neither of these analytical methods enables a TFA naturally occurring in basic food to be distinguished from a TFA formed during an industrial process.

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“…Maintenant des colonnes prêtes à l'emploi sont commercialisées. Une séparation des isomères du 18:1 a été décrite par Adlof [23] en utilisant celles-ci. De plus, les 7 isomères de l'acide α-linolénique ont été séparés et identifiés [24] en utilisant une colonne Nucleosil 5SA imprégnée au nitrate d'argent (Fig.…”

Section: Utilisation De Différentes Techniques Chromatographiques Pouunclassified

Analysis of conjugated and trans fatty acids after derivatization (in French)

Berdeaux¹,

Juanéda²,

Sébédio³

1998

Analusis

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Fatty acid methyl esters can be prepared easily by direct acid transesterification. If conjugated fatty acids are present, soft techniques must be used. In spite of new polar phases and capillary colums, the complete separation of all the fatty acids cannot be obtained by GC. However, the utilisation of silver ion HPLC and TLC helps to resolve some of the isomers. The derivatisation of fatty acids in DMOX, picolinyl and MTA derivatives enable the determination of the double bond position by GC-MS. GC-FTIR achieved the determination of the geometrical configuration. L es isomères d'acides gras monoinsaturés sont généra-lement formés à la suite de l'hydrogénation catalytique des huiles alimentaires [1] alors que les acides gras trans polyinsaturés (AGPI) apparaissent pendant la désodo-risation ou la friture [2,3]. Ceux-ci sont principalement formés à partir de l'acide linoléique (cis-9, cis-12-18:2) Il a été récemment montré que certains isomères d'acides gras polyinsaturés pouvaient également être métabolisés par l'animal [6,7]. Les mélanges d'isomères formés sont géné-ralement complexes et nous décrirons ci-dessous les diffé-rentes méthodes utilisées qui permettent leur quantification dans les différents aliments mais aussi l'analyse structurale des métabolites présents dans les échantillons biologiques. Utilisation de différentes techniques chromatographiques pour l'analyse des esters méthyliques d'acides gras trans et conjuguésLa dérivation des acides gras en esters méthyliques est la technique la plus utilisée pour l'analyse des lipides par chromatographie en phase gazeuse.Différentes méthodes sont utilisées pour la dérivation des acides gras à partir d'une matrice lipidique complexe comme les triglycérides ou les phospholipides [8]. Les esters méthy-liques sont couramment préparés par tra n s e s t é ri fi c at i o n directe des triglycérides ou des phospholipides en présence d'un catalyseur qui est soit acide (HCl, H 2 SO 4 , BF 3 dans le méthanol) soit basique (méthanolate de sodium ou de potassium). Par contre, la saponification suivie d'une estérifica-tion des acides gras libérés est, de nos jours, une méthode moins utilisée.Le choix de la méthode de méthylation repose en grande partie sur la présence d'acides gras conjugués dans l'échan-tillon. En 1972, Koritala et al. [9] ont signalé la présence d'artefacts au cours de la méthylation avec du BF 3 -métha-nol. Shantha et al. [10], qui ont étudié différentes méthodes de méthylation, ne recommandent pas l'utilisation de catalyseur acide. En effet, la transestérification en présence de c at a lyseur acide est réalisée à haute températ u re (90 à 100 °C) ce qui entraine l'isomérisation des doubles liaisons conjuguées, d'où une augmentation importante de la teneur d'isomères di-trans comme le montre la figure 1.

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Analysis of the monoenoic fatty acid distribution in hydrogenated vegetable oils by silver‐ion high‐performance liquid chromatography

Cited by 51 publications

References 15 publications

Enhanced Resolution of Conjugated Linoleic Acid Isomers by Tandem-Column Silver-Ion High Performance Liquid Chromatography

Enhanced Resolution of Conjugated Linoleic Acid Isomers by Tandem-Column Silver-Ion High Performance Liquid Chromatography

Analytical methods for determination of trans fatty acid content in food

Analysis of conjugated and trans fatty acids after derivatization (in French)

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