They simply screw in and out, so you should be able to just back them out, counter clockwise.
Even if they are super glued in, I would imagine you will be able to break the bond while trying to unscrew them.
You might have a problem if they are PVC glued in. PVC creates a chemical and mechanical bond by melting the 2 items and bonding that way. You can try to back them out or you can use some tubing and go to another male barb thread to a female 3/4 thread and thread the quick connect to that. It will look a little odd but it will work if you cant get them appart.
I just removed my barbed fittings to install the quick connects. The fittings were superglued in and I could not get them out. I used a hair dryer around the fitting and got it nice and warm and the fittings broke loose with just a little force, worked great!
it can be done with a heat gun ,heat up the black ring untill it softens a bit.Than stick a screwdriver ""carefully""between the fitting and the black ring.
The ring will flex a little and you,ll remove the first pvc cement.
Tricky job you can damage the threads