I’m using water too - with a standard Quechers separation for my injection.
I’ve also seen people use ethyl acetate - when they freezer and grind the gummy using like PTFE coated bb’s for the grinding in the test tube.
The AOAC method for most “foods” says to use quechers when you are trying to separate the aqueous from the organic layers. Its worked for me. The specific method is for pesticides… the sample prep works just as good for potency, IMO.