[bonkers]

Hello,

I was doing an analyzis today with RP-HPLC with vitamines D2 and D3. After I Diluted the sample(jam) in few ml of water I added KOH in EtOH and heated the solution for 30 minutes. The thing I cant figure out is what reaction takes place between vitamin D and KOH. The next step was that I extracted it from the solution with hexane, which is probably related with the reaction.
D2
http://upload.wikimedia.org/wikipedia/commons/5/5f/Ergocalciferol.svg
D3
http://upload.wikimedia.org/wikipedia/commons/7/79/Cholecalciferol.svg

I would also appreciate if anyone told me how to post the pictures in smaller format

Edit by Borek: links edited.

[fledarmus]

I'm not sure I understand exactly what you are trying to say, but from the way you've described it, it doesn't sound like the vitamin D is reacting with the KOH at all. The vitamin D is being extracted unchanged into the hexane. The KOH is reacting with other components in your jam so they will remain in the water.

[bonkers]

I'm not sure I understand exactly what you are trying to say, but from the way you've described it, it doesn't sound like the vitamin D is reacting with the KOH at all. The vitamin D is being extracted unchanged into the hexane. The KOH is reacting with other components in your jam so they will remain in the water.

I think i was misled by the protocol or just don´t remember correctly. It said that vitamines are saponificated, but it actually ment that fats in the sample are saponificated so they wouldn´t interfere with my chromatographic peaks later in the analysis? Am I correct?

[Borek]

I would also appreciate if anyone told me how to post the pictures in smaller format

I don't think you can have any control over the image size, they are displayed in their native size.

[Babcock_Hall]

bonkers,

I was just about to suggest saponification myself, although it is just an educated guess.  There are phospholipids in material derived from any living tissue.  If you turn esters of fatty acids into their carboxylate salts, they become more polar and are less likely to be found in the hexane layer.

[bonkers]

Thanks to all that replied