Tocopherol & Tocotrienol Part II

[leadazide]

Hi everybody

Having used this forum extensivly I feel it’s time to give a little back. For once I don’t only have questions but I'm posting a (almost) complete method . With inspiration in ljc’s method in post “Tocopherol & Tocotrienol by HPLCâ€

[ym3142]

HI, Leadazide,
Thanks for the sharing.
It is interested to me because these are very hydrophobic molecules/isomers I never work on.
Do you the following answers?
what is the retention time if in a C18 column with mobile phase of 98% ACN or THF or IPA?
what if it's an endcapped RP column?
Do you know if the DIOL is better than CN or Amino due the different column stationary chemistry? or you/they happened to start from DIOL?
Do you know anything other reason of choosing DIOL?
what if in a straight silica gel column?
Thanks and have more funs,

[Bryan Evans]

These compounds were separated nicely on our
Unison UK-Silica column:

http://www.silvertonesciences.com/modul ... TI166E.pdf

[leadazide]

Bryan: Darn, that seperation looks sweet!!

ym3142: On the RP system we use a ODS hypersil 125mm x 4.6mm column with methanol:water 96:4 at 1 ml/min. This gives us a rt of 7 for delta, 9.5 for gamma + beta and 11 for alpha. Right now our system that runs the RP method is occupied with other methods, so I can't check with your specific eluent in the near future.. sorry:(

The reason we use the DIOL is that i read several different examples of methods which used this column. I had tried with both CN, amino and a silia column.. I didn't get any proper seperation with these, but it might very well be the columns that are ruined since they were just lying around and are at least 10+ years old. So when I had to order a new column anyway I ordered the DIOL, since I had seen example chromotograms with this and liked what i saw plus we didn't have a DIOL column and I like to have lots of options lying around in case we have to try something new in the future..

[ym3142]

If were me, I will try some of C18, C8, Phenyl columns; then, their endcapped(hypersil is). I am sure one of these column will be good.
though you have try different organic and mixture, buffer, addictives, temperature, gradient, even PH. good luck.

[Norikazu Nagae]

I recommend C30 RPcolumn for separation of tocopherols. It can separate gamma and beta tocopherol at 15 C completely. You can see its separation on the following website:

http://develosil.net/eappli019.htm