Hi Branlorio,
Asking to duplicate a particle object is a trick question!
Do you only want the particle object?
Do you want the particle object and its emitter?
Do you want the particle object, its emitter and forces?
Do you want all the expressions that connect the particle object to all the of the force and collision objects?
So, if you'd like a copy of the particle object making a copy by duplicating it usually doesn't work very well, even with the special where you get the inputs and outputs, as the expressions and other things tend to break or stop working.
The best way to make a copy of what you are after, in my opinion would be to strip everything in the scene that you do not require and still have the particle object and the other components.
Rename the particle object to particleCopy or something different from the one you want. Same goes for any other object, like the emitter, forces, or collision objects (exception see below)
Then once you are happy, save it as a separate scene.
Import that back into the original scene and things should work.
Exception Collisions: If you have collision objects, you probably shouldn't have them in the copy you saved, you would then reconnect them once you bring back into the original scene,
Making copies of particles systems is not as easy as duplicating regular objects.
C