I'm thinking of using the vinegar I have in my cupboard for use with chips(french fries) to extract harmalas alkoloids from syrian rue seeds. This is what it says:

Malt Vinegar (From Barley),
Roasted Barley Malt Extract,
5% acidity.

Allergy Advice:
Contains Barley, Gluten

Is this vinegar okay to use or do I have to buy a different kind?

i dono about malt. it contains too much impurities. why not use normal vinegar its easy to obtain, cheep and its distilled.

Seraph, personally i have as a rule that the purer the solvents the purer the product. In chemistry they say "crap in ,crap out" , but as far as extractions go it makes sense. In an extraction you try to remove unwanted material, its not practical to introduce more unwanted material. For example if i was to choose between malt vinegar and common vinegar i would choose the second, if i had the option i would go for distilled vinegar or...even lab grade acetic acid.

I think tis worth it to wait till you can have cleaner vinegar.

Unless, perhaps, you're attempting a very certain kind of experience. Where do you want your trip to take you? An English pub?

do not use malt vinegar, get pure white stuff.

But ya, as others have said, go get some distilled vinegar. It's cheap, easy to find, works well -- and shouldn't you have some around if you're working with lye (if you are)?

No rush, take you're time. Do it right.