I use NoDoFollow 1.1. It's an extension used in Mozilla. The red color indicates "no follow" and and another color indicates follow.
Also, you can check it by the following method: ( It's manual checking, might be hectic)
1) Go to the link and hover a mouse over it and click right click the mouse and click "inspect element"
2) Check the code and if href says "nofollow" any where then it's no follow link.