First off, propane is odorless. What you are smelling is methyl mercaptan which is detectable to the human nose at 3 parts per BILLION. Lower explosive limit of propane is 2.1 parts per million. The point is a little bit of smell goes a long way.
Are you sure you are smelling a leak that you can't find or smelling residual odor? If it is a continuous constant odor don't take a chance until you have found and addressed the leak. Take it to a propane dealership if necessary.
Do not put teflon on any brass fitting.