Separation of tocopherols

The separation of substances of highest purity from natural mixtures by chromatography is of increasing interest. An example is the production of natural tocopherols (vitamin E) from vegetable oils. The purity that can be obtained by conventional processes like distillation or extraction is limited due to the multiplicity of components with similar extraction behavior. On the other hand by chromatographic separations it is even possible to obtain each single tocochromanol with high purity. 

The difference m - ml is decreasing and therewith the maximal feed flow rate. 

Finally simulations were done with all the optimized parameter (feed concentration 15mg/ml column length 6cm, column configuration 1/2/2/1). This enhanced the specific productivity to more than 1.3 kg/lspd. A comparison of the optimized SMB process with the also optimized elution process showed, on the 

1 Heuer, C. Hugo, P. Seidel-Morgenstern, A. Experimental investigation and modeling of closed-loop recycling in preparative chromatography. Chem. Eng. Sci., 1995, 50, 1115-1127. 

2 Heuer, C. Kniep, H. Falk, T. Seidel-Morgenstem, A. Vergleich verschiedener verfahrens technischer Konzepte der praparativen Fltissigchromatographie. Chem.-Ing.-Tech., 1997, 69,1535-1546. 

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Strohschein, S., Pursch, M., Lubda, D., and Albert, K., Shape selectivity of C-30 phases for RP-HPLC separation of tocopherol isomers and correlation with MAS NMR data from suspended stationary phases. Anal. Chem., 70, 13, 1998. 

Brunner et al [1, 2] investigated separations of fatty acids according to chain length, using methyl esters of different carbon chain length from C14 to Cl8, separation of tocopherols from a by-product of the edible oil production and separation of fish oil esters [3], Stahl et al [4] proposed the supercritical fractionation of orange peel oil and Reverchon et al [5,6] of an orange flower concrete. Different authors treated citrus peel oil [7,8] and citrus oil [9-12]. 

Tan, B. and Brzuskiewicz, L. 1989. Separation of tocopherol and tocotrienol isomers using normal- and reverse-phase liquid chromatography. Anal. Biochem. 180 368-373. 

Figure 1.11 UV chromatograms (295 nm) of the separation of tocopherol isomers (1, 8-tocopherol 2, 7-tocopherol 3, (3-tocopherol 4, a-tocopherol 5, a-tocopherol acetate (a) analytical separation (b) with a 200-fold amount of sample...

S. L. Abidi and T. L. Mounts, Separations of tocopherols and methylated tocols on cyclodextrin-bonded silica, J. Chromatogr., A 664 130 (1994). 

Figure 11.3 Normal-phase HPLC separation of tocopherols (Ts) and tocotrienols (T3s) from barley kernels. A. Detection via fluorescence, ex 294 nm, em 326 nm, B. Detection via a charged aerosol detector. For FIPLC parameters see Moreau et al. (2006).

Carabias-Martinez, R. Rodriguez-Gonzalo, E. Smith, N.W. Ruano-Miguel, L. 2006. Use of polar-embedded stationary phase for the separation of tocopherols by CEC. Electrophoresis 27 4423 430. 

Byproducts of conventional oil extraction and refining have been investigated as raw materials for the concentration of bioactive components. Birtigh et al. (115) investigated SFE of carotenes and tocopherols from waste products of pahn oil production (i.e., the residue of mechanical processing and palm leaves). Ibanez et al. (116) studied the separation of tocopherols from olive byproducts using fractional... 

Djakovic-Sekulic, T. Perisic-Janjic, N. Pyka, A. Correlation or retention of anilides and some molecular descriptors. Application of topological indexes for prediction of log k values. Chromatographia 2003, 58 (1/2), 47-51. Pyka, A. Sliwiok, J. Chromatographic separation of tocopherols. J. Chromatogr., A 2001, 935, 71-76. 

Peper S, Cammerer S, Johannsen M, Brunner G. Supercritical fluid chromatography process optimization of the separation of tocopherol homolgues. In Kikia I, Perrut M, eds. Proceedings of the 6th International Symposium on Supercritical Fluids, 1999 563-568. 

The detection and quantification of tocopherols, carotenoids, and chlorophylls in vegetable oil were effectively used for authentication pnrposes. The presence of tocopherols, carotenoids, and chlorophylls influence the oxidative stability of vegetable oils and their potential health benefits. Puspitasari-Nienaber et demonstrated the application of a rapid and reliable analysis method of direct injection of C-30 RP-NPLC with electrochemical detection for the simultaneous analysis of the above mentioned substances. Aliquots of vegetable oils were dissolved in appropriate solvents and injected directly without saponification, thus preventing sample loss or component degradation. Thus the effective separation of tocopherols, carotenoids, and chlorophylls was achieved. 

Fanali, S. Camera, E. Chankvetadze, B. D Orazio, G. Quaglia, M.G. Separation of tocopherols by nano-liquid chromatography. J. Pharm. Biomed. 2004, 35, 331-337. 

These materials are suitable for RP-TLC owing to their lipophilic properties. The commonly used RP layers consist of dimethyl-(RP-2), octyl-(RP-8), octadecyl-(RP-18), and phenyl-bonded silica gel, type 60, with different mean particle sizes and particle size distributions. Recently, C30-modified silica gel was proposed for the separation of tocopherol homologues. 

Source From Chromatographic separation of tocopherols, in J. Chromatogr. 

Although this paper is ostensibly to differentiate packing materials, it also provides excellent information regarding the separation of tocopherols (a, P, y, and S) and tocotrienols (a, p, y, and d). Excellent separation of all compounds was achieved in 20 min on a silica colunm (A = 294 nm, ex 326 nm, em) using a 96/4 hexane/1,2-dioxane mobile phase [666]. A diol column was also effective when a 94/4 hexane/methyl /-butyl ether mobile phase was used. Aminopropyl columns were less effective overall. 

Separation of tocopherols from their decomposition products... 

Separation of tocopherols from other fat-soIuble vitamins, e.g. in pharmaceutical preparations Detection of antioxidants, including vitamin E, in foods... 

Separation of tocopherols from their decomposition products. Silica gel lends itself conveniently to the separation of a-tocopherol from its oxidized decomposition products, including a-tocopherylquinone, a-tocopherylhydroquinone, and various partly characterized monomeric and dimeric compounds. These compounds can be prepared by in vitro oxidation, but some of them have also been detected by TLC in biological materials, e.g. rat liver (60). 

Separation of tocopherols from other fat-soluble vitamins. a-TocopheroI can be readily resolved by TLC on silica gel or alumina from other fat-soluble vitamins (61). On silica gel, it migrates ahead of the D vitamins but more slowly than retinol (vitamin A) and phylloquinone (vitamin K]). The differentiation of the free tocopherol and its acetate and succinate esters, which are frequently used in pharmaceutical preparations, is also straightforward (61). 

Figure 3 Separation of tocopherols and tocotrienols by (a) nomial-phase and (b) re-versed-phase chromatography. Chromatographic conditions (a) Column, Zorbax SIL, 250 X 4.6 mm mobile phase, hexane isopropanol (99 1, v/v), (b) Column, Zorbax ODS, 250 X 4.6 mm mobile phase, acetonitrile methanol dichloromethane (60 35 5, v/v) detection, UV, 295 nm. Peak identification 1, a-tocopherol 2, a-tocotrienol 3, -tocopherol 4, y-tocopherol 5, y-tocotrienol 6, 5-tocopherol 7, 5-tocotiienol. (From Ref. 91 -)... 

Another partial separation was achieved on an uncommon column material of Japanese origin (YMC-PACK A-302 S-5 ODS) eluted with propanol-water (35 65, v/v) (39). The most complete reversed-phase separation so far of p- and y-tocopherol is based on a pentafluorophenyl (PFPS) bonded phase and methanol-water as the eluent, as described by Richheimer (42) (Fig. 5). In their fundamental study on the separation of tocopherols on reversed phases, Abidi and Mounts corroborated the results of Richheimer with respect to the superiority of the PFPS phase for the separation of positional isomers, including 5,7-dimethyl-... 

SL Abidi, TL Mounts. Reversed-phase high-performance liquid chromatographic separations of tocopherols. J Chromatogr 782 25—32, 1997. 

WT Wahyuni, K Jinno. Separation of tocopherols on various chemically bonded phases in microcolumn hquid chromatography. J Chromatogr 448 398-403, 1988. 

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