Not sure about the Ethyl Vanillin I used this is the description on the Website:
This product is Ethyl Vanillan Crystals in USP 99.8+% Propylene Glycol (PG) Solution
Around .5%, 1% usage is the norm, maximum will be around 2.5%-5%. Never go > 5% since taste will be muted, less is more using EV
Recommended 1-2 drops per 5ml eliquid