A Proposed Modification of Emmerie's Iron-Dipyridyl Method for Determining the Tocopherol Content of Oils

Parker, W.; McFarlane, William

doi:10.1139/cjr40b-050

Cited by 68 publications

(13 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…grade (96% tocopherol). It was purified by eight repetitions of the acid and alkali wash procedure of Parker and McFarlane (15). The product gave a single spot in several systems of thin layer chromatography (TLC) and UV absorbance in agreement with literature values.…”

Section: Introductionsupporting

confidence: 81%

See 1 more Smart Citation

An addition compound of oxidized tocopherol and linoleic acid

Porter

Levasseur

Henick

1971

Lipids

View full text Add to dashboard Cite

There is evidence that an addition compound of oxidized dl-alpha-tocopherol and linoleic acid is formed when the components are adsorbed in mixed monolayer on silica gel at a molecular ratio of 1:20, and subjected to heating in air at 80 C. A relatively nonpolar tocopheryl quinone is also formed in smaller amounts. These are the major tocopherol oxidation products isolated in this system and do not correspond to any known to the authors. The addition compound has about the same mobility as linoleic acid in most thin layer chromatography (TLC) and chromatographic systems, but can be isolated by successive chromatography on silica and gel filtration on Sephadex LH-20. It yields a single spot in TLC in several systems. The elemental analysis is reproducible and consistent with a simple addition compound of linoleic acid and bivalently oxidized tocopherol. The compound has a carboxyl group which can be esterified. The ester has about the same TLC mobility as methyl linoleate. The molecular weight of the ester is 722.6. The UV spectrumoshows a single peak, ETOH = 3000 A, E = 4.74. The IR max spectrum shows a very strong chroman ether band at 9.12 At, a strong methyl band at 7.24 At and carboxyl but no hydroxyl absorption. The NMR spectrum shows, in contrast to that of tocopherol, a reduction in aromatic methyl protons, a carboxyl proton exchangeable with deuterium oxide, but no hydroxyl proton. The compound does not reduce Emmerie-Engel reagent prior to treatment with concentrated hydriodic acid, nor do the ether-extractable products after such treatment. The present data are consistent with an addition product whose bridging group is a new chroman ring.

show abstract

Section: Introductionsupporting

confidence: 81%

“…The adduct was characterized by using TLC on Silica G with benzene, esterification with boron trichloride and methanol reagent (18), reaction with the Emmerie-Engel spray reagent and with 58% hydriodic acid (15,19). Analytical data for the compound are shown below.…”

Section: Introductionmentioning

confidence: 99%

An addition compound of oxidized tocopherol and linoleic acid

Porter

Levasseur

Henick

1971

Lipids

View full text Add to dashboard Cite

show abstract

“…grade, Nutritional Biochemicals Corp., Cleveland, Ohio) and natural d-alpha-tocopherol (Distillation Products Industries, Rochester, N.Y., and Fisher Scientific Co., Fairlawn, New Jersey) were used. The synthetic material was used either as received (96% C29H5oO 2) or after eight repetitions of an acid and alkali wash procedure (8). The natural material was used directly from the ampoule and gave a single spot in all systems of thin layer chromatography (TLC) and UV absorption was in agreement with literature values.…”

Section: Experimental Procedures Materialssupporting

confidence: 63%

UV Spectrophotometry of autoxidized lipid monolayers while on silica gel

Porter

Levasseur

Jeffers

et al. 1971

Lipids

View full text Add to dashboard Cite

Autoxidation reactions of linoleic acid and tocopherol and of mixtures of the two have been monitored in the dry monolayer state while adsorbed on silica gel, by means of silica slurry spectrophotometry and oxygen uptake measurements. The UV absorbance of the products of linoleic acid alone is similar to that of previously characterized compounds, but that from tocopherol is not referable to any oxidation products known to the authors, regardless of whether the determination is made while adsorbed on silica or on the extracted products. Two compounds, designated A and B, having absorbance in ethanol at 2610–2670 and 3000 A, respectively, are the major products of tocopherol oxidation detectable by UV above 2200 A. They are a tocopheryl quinone without a hydroxyl group and an adduct of linoleic acid and oxidized tocopherol. The product distribution suggests that tocopherol may have a restricted migration in this system.

show abstract

“…of the petroleum ether extract of the unsaponifiable fraction were shaken briefly with 2 ml. aqueous sulfuric acid (85% H 2 S0 4 by volume), according to Parker and McFarlane (1940), and then centrifuged clear of acid. This treatment removed some unsaponifiable constituent which, otherwise, was eluted from the chromatographic column together I. BARTOV, P. BUDOWSKI AND S. BOKNSTEIN with the AT and interfered with its colorimetric determination.…”

Section: Experimental Methods and Resultsmentioning

confidence: 99%