Need a method to detect the amount of a-tocopherol in oil. Cant seem to find a robust and precise method. This can be either GC or HPLC!
Use ODS column with a methanol–water mobile phase at 290nm, flow= 1ml/min for identification.
A method with HPLC:
Manzi P., Panfili G., Esti M., Pizzoferrato L. 1998. Natural antioxidant in the unsaponifiable fraction of virgin olive oils from different cultivars. J. Sci. Food Agric.,77 115-120.
This method is for dairy produts
Manzi P., Panfili G., Pizzoferrato L. 1996. Normal and reversed phase HPLC for more complete evaluation of tocopherols, retinols, carotenes and sterols in dairy products. Chromatographia 43, 89-93
Fat soluble vitamins in Normal fase:
Panfili G., Manzi P., Pizzoferrato L., 1994. HPLC simultaneous determination of tocopherol, carotenes, retinol and its geometric isomers in Italian cheeses. Analyst, 119, 1161-1165.
Attached you can find the IUPAC Method for Determination of Tocopherols and tocotrienols in vegetable oils by HPLC
Hi,
We have been using for long time the ISO method, it is much more modern, than IUPAC. We use a diol column and n-heptane-THF (3,85-4,0%) eluent with FLD detection. Of course you need pure standards of alpha-, beta-, gamma-, and delta tocopherol for calibration.
If needed you can even measure the tocotrienols as well.ISO 9936:2006
Column e.g. Lichrospher 100 diol
The simplest way is using HPLC with fluorescence or UV detection. You can choose between normal or reversed phase. In reversed phase, the beta and gamma isomers will co-elute.
The HPLC instrument used was equipped with S-1122 dual piston solvent delivery system. Briefly, oil (100 mg) was dissolved into 5mL methanolic KOH (80%) and subjected to incubation at 65 0C for 30 min. After the saponification was completed, the mixture was allowed to cool down to room temperature. For extraction purposes, added 3mL distilled water and 10mL n-hexane. The hexane layer recovered, containing tocopherols components, was evaporated to dryness under nitrogen streaming and then added 1.0 mL mobile phase to redissolve the residue. Tocopherol isomers were separated on a Hypersil ODS reverse phase (C18) column (250 x 4.6 mm, 5 μm particle size; Thermo Hypersil GmbH, Germany) fitted with a C18 guard column. The mobile phase used was a mixture of methanol: acetonitrile: dichloromethane (50:44:6, v/v/v) at a flow rate of 1.0 mL/min. The detection was performed at 295 nm using a S-3210 UV/VIS diode array detector. Tocopherol isomers were identified on the basis of matching of their retention times with those of pure standards of tocopherols and quantified on the basis of peak area using standard calibration curve of the pure compounds.
Please kindly find the chromatography
ıf you need some detail information please contact with [email protected]
Several reversed-phase high-performance liquid chromatography (RP-HPLC) studies for the determination of tocopherols in oils are reported. You rever the following publications:
J.I. Rader, C.M. Weaver, L. Patrascu, L.H. Ali, G. Angyal (1997). Food Chem. 58(4): 373.
H.E. Indyck, (1988). Analyst 113: 1217.
F. Dionisi, J. Prodolliet, E. Tagliaferri, (1995). J. Am. Oil Chem.Soc. 1505.
And also the following links:
http://pubs.acs.org/doi/abs/10.1021/jf4038858
http://www.sciencedirect.com/science/article/pii/S0889157511001207
http://www.notulaebotanicae.ro/index.php/nbha/article/view/9027
http://www.uaiasi.ro/revista_zoo/ro/documente/Pdf_vol/Z109_Denisa_Rachieru.pdf
We use the following method for the separation of all eight tocopherols and tocotrienol and I know we have used this method for oil samples as well (with saponification) http://www.ncbi.nlm.nih.gov/pubmed/22560347
or http://www.sciencedirect.com/science/article/pii/S002196731200619X
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