Can i be fired in arizona for testing positive for drugs despite only having legal "bath salts" in my urine?

Also known as MCat and Plant Food, Methadrone is a legal stimulant and I am worried about results from drug test at work last week. Arizona is a Right-to-Work state so I understand how unprotected I am however if I show positive for stimulants and they fire me based on this test, what are my options for collecting unemployment, preserving my reputation and taking legal action against company for unlawful discharge. I will be sure to get papers explaining their reasons, of course.