Analysis of vitamin E in food and phytopharmaceutical preparations by HPLC and HPLC-APCI-MS-MS

Abstract

The analysis of ~, 13, y, 8-tocopheroJs, trienoJs, ~-tocopheryJ acetate and nicotinate (vitamin E) in complex matrices was carried out using a new liquid chromatographic (HPLC) method giving better separation efficiency, selectivity and sensitivity than that described in the literature. The use of normal-phase (NP)-HPLC on silica gel with isooctane-diisopropylether-l,4-dioxane as optimized mobile phase yielded higher resolution than conventional reversed-phase (RP)-HPLC using methanol mobile phase. Identification of peaks was by UV-absorbance at 295 nm, diode array, or fluorescence detection ()~ex = 295 nm, )~ex = 330 nm). The latterwas found to be more selective and ten times more sensitive than UV-absorbance detection. A quadrupole, ion-trap mass spectrometerwith an atmospheric-pressure ionization (APCI) interface was used to detect vitamin E constituents in the femtomole range. With collision-induced dissociation (CID) in the ion source, which gave characteristic fragmentation, the identity of the investigated compounds could be confirmed. Plots of peak area versus amount injected allowed quantitation of ~, 13, y, 8-tocopherols and -trienols, ~-tocopheryl acetate and nicotinate in real samples such as peanut, almond, spinach, spelt grain bran, latex and tablets. The method described offers fast identification and quantitation of vitamin E constituents of complex biological origin.

Simultaneous determination of carotenoids, tocopherols, and γ‐oryzanol in crude rice bran oil by liquid chromatography coupled to diode array and mass spectrometric detection employing silica C30 stationary phases

“…In the LC of tocopherols employing silica C18 as a stationary phase the critical pair is the coeluting b-and c-tocopherols [35]. RP separation of b-and c-tocopherols is an important goal in vitamin E analysis as they cannot be distinguished by a mass spectrometer.…”

“…Therefore, the addition of an antioxidant is helpful [34]. The preferred separation technology for the analysis of tocopherols is LC [35]. For satisfactory resolution of carotenoids and tocopherols applying RP-LC, silica phases derivatized with C8-and C18-phases have been substituted by C30 [36,54,55], pentafluorophenyl groups (PFP) [37], or octadecyl polyvinyl alcohol (ODPVA) [38].…”

Influence of the pore structure on the properties of silica based reversed phase packings for LC

“…Isocratic separation of all tocopherol isomers cannot be achieved on C 18 phases [1,33]. The C 30 phase is adequate for the separation of the isomers of Vitamin E. The separation of the critical pair of tocopherol b and c is largely effected by the pore structure of the phase (Figure 9).…”

The Modern Art of Identification of Natural Substances in Whole Plants

“…Carotenoids (Hao et al 2005) and fat-soluble vitamins (Stoggl et al 2001) are analyzed in LC-MS with APCI or APPI. For example, Stoggl et al (2001) achieved quantification in the femtomole range of vitamin E and some other tocopherol derivatives in food and phytopharmaceutical preparations by HPLC-APCI-MS/MS. Recently, six fat-soluble vitamins (A, E, D2, D3, K1 and K2) and six water-soluble vitamins (B1, B2, B3, B6, B7 and B12) were analyzed simultaneously in LC-APPI-MS/MS.…”