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tocopherol analy.method for oils by gas chromatog.
Posted: Fri Jan 27, 2006 12:48 pm
by neval
Do you know about a method about tocopherol analysis by gc..I know that tocopherol are usually identified by hplc..but in my labor I have only gc and I working with dl-alpha tocopherol in refined sunflower oil..
Are the methods same as the normal oils analy?Usually I take a few oil,added 5 ml metyllent solvent( KOH),and solvent is heptan..So,can I use the same method....
Also,one more question:) I read hexadecyl hexadecanoate,is it for the same as heptan,or what?
thank you!
Posted: Fri Jan 27, 2006 4:28 pm
by Consumer Products Guy
I'll assume that you're assaying dl-alpha tocopherol, not dl-alpha tocopheryl acetate. We've done both by GC, straightforward, high temperaturs are required. Now dl-alpha tocopherol is not all that stable, so personally I would not use KOH or saponify first. The dl-alpha tocopherol is more soluble in solvents such as N,N-dimethylformamide (DMF) and alcohols than is the sunflower oil. You could use hexane or heptane as solvent, but I think I'd use DMF or alcohol, heat and stir, cool it (most of the sunflower oil should separate and float on the top), and inject the solvent portion into the GC. If I understand your wording correctly, hexadecyl hexadecanoate would probably be an internal standard, and is the ester of hexadecanoic acid and hexadecanol (cetyl palmitate).
Posted: Sat Jan 28, 2006 3:03 pm
by neval
thank you..
you said that high temp programs..I heard that ; program begin with 240 C and goes to 290 C..is it true...and you said that DMF ...so fırstly,how much mg dl-alpha tocop dissolved in alcohol( methanol,ethanol isnt it) ..and I use this tocopherol as antioxidants,
Should I look fırstly alpha tocopherol,and another analysıs oil+tocopherol?
And you meant that I dont have to metillent solutıon(saponification)..so I should firstly dissolve tocopherol in DMF or alcohol,and then I can use heptan as solvent.( is the procedure same as in free fatty acid comp..)
if you answer,thank you...
Posted: Sat Jan 28, 2006 3:04 pm
by neval
thank you..
you said that high temp programs..I heard that ; program begin with 240 C and goes to 290 C..is it true...and you said that DMF ...so fırstly,how much mg dl-alpha tocop dissolved in alcohol( methanol,ethanol isnt it) ..and I use this tocopherol as antioxidants,
Should I look fırstly alpha tocopherol,and another analysıs oil+tocopherol?
And you meant that I dont have to metillent solutıon(saponification)..so I should firstly dissolve tocopherol in DMF or alcohol,and then I can use heptan as solvent.( is the procedure same as in free fatty acid comp..)
if you answer,thank you...