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

The analysis of alpha,beta,gamma,delta -tocopherols, trienols, alpha -tocop heryl acetate and nicotinate (vitamin E) in complex matrices was carried ou t using a new liquid chromatographic (HPLC) method giving better separation efficiency, selectivity and sensitivity than that described in the literat ure. The use of normal-phase (NP)-HPLC on silica gel with isooctane-diisopr opylether-1,4-dioxane as optimized mobile phase yielded higher resolution t han conventional reversed-phase (RP)HPLC using methanol mobile phase. Ident ification of peaks was by UV-absorbance at 295 nm, diode array, or fluoresc ence detection (lambda (ex) = 295 nm, lambda (ex) = 330 nm). The latter was found to be more selective and ten times more sensitive than UV-absorbance detection. A quadrupole, ion-trap mass spectrometer with an atmospheric-pr essure ionization (APCl) interface was used to detect vitamin E constituent s in the femtomole range. With collision-induced dissociation (CID) in the ion source, which gave characteristic fragmentation, the identity of the in vestigated compounds could be confirmed. Plots of peak area versus amount i njected allowed quantitation of alpha,beta,gamma,alpha -tocopherols and -tr ienols, alpha -tocopheryl acetate and nicotinate in real samples such as pe anut, almond, spinach, spelt grain bran, latex and tablets. The method desc ribed offers fast identification and quantitation of vitamins E constituent s of complex biological origin.