For how long should I boil veggies without compromising or losing its nutrients?

I usually boil until tender, but that's for potatoes, squash and other big chunks but for leafy greens, just less than 10 mins after boiling. Here's a guide on how long you should boil your veggies http://recipes.howstuffworks.com/tools-and-techniques/how-to-cook-vegetables24.htm