HPLC analysis of phenolic antioxidants, tocopherols and triglycerides

Abstract

Triglycerides, together with nine synthetic phenolic antioxidants most commonly used to prevent oxidation of edible oils and fats, as well as the natural antioxidants tocopherols and a-tocopherol acetate, were separated by high performance liquid chromatography by means of a reversed phase Cls-column and gradient elution with water/acetonitrile/methanol/isopropanol. Besides dilution of the oil with isopropanol/hexane, no further example preparation was required. UV detection was applied. The synthetic antioxidants propyldodecylgallate, octyldodecylgallate, dodecylgallate, 3-tert-butyl-4-hydroxyanisol, tert-butylhydroquinone, 3,5-di.tert.butyl-4-hydroxytoluene, 2,6.di-tert-butyl-4.hydroxymethylphenol, 2,4,5-trihydroxybutyrophenone and nordihydroquaiaretic acid, as well as a-and 6-tocopherol and atocopherol acetate were base-line separated; f~ and ytocopherol, however, eluted together. The triglycerides, detected at ~ --215 nm, were separated according to their partition number. The absorption at ~ --215 nm revealed saturated and unsaturated triglycerides. The absorption at ~ --280 nm indicated triglycerides with conjugated unsaturation, relating information about refining and heat treatment of the oil. Oxidized unsaturated triglycerides showed absorption at k = 230 nm. Triglycerides of ricinoleic acid, a hydroxymonounsaturated acid, gave identical UV spectra. The simultaneous detection of antioxidants and triglycerides may be used to study inhibition effects by antioxidants in oils.

Application of Chromatographic and Infra-Red Spectroscopic Techniques for Detection of Adulteration in Food Lipids: A Review

“…Analysis of tocopherols present in oils and fats could be easily done using HPLC system equipped with normal-phase column and a florescence detector [63]. However, HPLC systems equipped with reversed-phase column (RP-HPLC) and UV detection were also found to give good results [64]. According to some recent reports, RP-HPLC also has the advantage of faster chromatographic runs, faster equilibration time and better reproducibility of retention times [65].…”

Lipase-catalyzed acidolysis of fish liver oil with dihydroxyphenylacetic acid in organic solvent media

“…Generally its application is oriented towards the specific detection and potential identification of chemicals in the presence of other chemicals (in a complex mixture). LC-MS has been used for the structural characterization of lipids and phenolic lipids (Kontogianni et al, 2001;Andrikopoulos, 1991 and.…”

Validação de metodologia para a determinação simultânea dos antioxidantes sintéticos em óleos vegetais, margarinas e gorduras hidrogenadas por CLAE/UV

“…A maioria dos trabalhos relatados tem utilizado eluição por gradiente [18][19][20][21][22]24,25 embora eluição isocrática tenha sido usada em alguns casos. [26][27][28][29] Métodos para a separação de antioxidantes em fase normal têm sido propostos por Van Niekerk e Du Plessis, 30 Indik e Woollard, 31 Anderson e Van Niekerk, 26 mas são pouco empregados, já que a utilização de fase normal apresenta a desvantagem de necessitar de misturas complexas de solventes para a fase móvel, que são tóxicos tais como dioxano-hexano, 30 hexano-cloreto de metileno-acetonitrila 31 e hexano-1,4-dioxano-acetonitrila, 22 enquanto que a fase reversa emprega solventes mais comuns como o metanol e acetonitrila e, portanto, tem a preferência dos pesquisadores.…”

“…A maioria dos trabalhos relatados tem utilizado eluição por gradiente [18][19][20][21][22]24,25 embora eluição isocrática tenha sido usada em alguns casos. [26][27][28][29] Métodos para a separação de antioxidantes em fase normal têm sido propostos por Van Niekerk e Du Plessis, 30 Indik e Woollard,…”