Chromatography Forum

I was thinking about this and the problems we had when first developing our acid profile here at the winery (12th and Maple Wine Company). We realized that if we didn't adjust the pH of the wine high enough that we would get poor retention of acetic acid. We originally started off just adding the wine straight onto a Restek SAX column and then realized that the pH of wine was below that of the pKa of acetic acid. (No makin' fun, I'm a genetics person, LC+SPE is totally new for me)

I was thinking that if there was a way to remove ONLY acetic acid from a wine with say a very large SPE column, 1-1/2 in diameter and 12 inches long that you could make Reverse Osmosis obsolete. Can anyone suggest someone who might like to collaborate on developing this type of method or suggest a current vendor of such things?

Thanks!

You won't be able to remove only acetic acid, other acids with lower pka will also be removed.

What exactly are you trying to achieve here?

I was thinking along the lines of having an in line solid phase filter to remove acetic acid only. I was curious if anyone knew of any very specific pKa extraction material. If there was a range like pKa 3.8-5.4 or 3.8 - 6.5 I would think that would retain the Tartaric acid while removing just the higher pKa acids.

I see. There are not specific pka extraction materials. There are strong and weak ion exchange material and they will work appropriately after using the necessary pH in order to ionize your acids or other compounds. In that way you are going to retain first strong acids and then acids starting with the lower pka. At the same time you might retain other anions...

From what you said so far, it looks to me that you search for a resin that will retain undesirable acids from the wine and after exctraction you will still give the wine for consumption, that is why you do not want of course to modify the pH of your wine or add anything in to it. What if the fermentation didn't go that well and we got more than 0.6 of acetic acid. The extraction column will take care of it. Why spend all these money and time and do tartaric acid stabilization by cooling tons of wine for several weeks? let's also use an extraction column. And why going in to the pain of doing a second fermentation (bacterial) in order to take care of the malic acid, the extraction column will take care of it. And this container of wine has created off-flavors... are we going to throw it away? What the hell, let's add some active carbon and see if that will take care of it... the active carbon will precipitate after all.

Although ion exchange and active carbon resins are being used for water softening and flavor elimination, they are not well suited for very complex mixtures where you want to discriminate which compounds you would like to retain. Also a lot of the resins are not intended for food consumption...

(Hopefully), you probably don't want to use the resins the way I described them I was just kidding...