This is probably the most basic brine that I know of for smoking salmon,
to a quart of water add,
1/2 cup "non" iodized salt,
1/2 cup sugar,
1/4 cup brown sugar,
crushed garlic clove.
I heat it so everything melts ,then cool it before adding the fish. Brine overnight and pat dry before placing on smoker.
I like basting with "pure" maple syrup or honey as it`s smoking, it adds a gorgeous glaze to it and helps it to retain it`s moisture.