Systems and methods are provided for authenticating working fluids. The systems and methods include exposing at least a portion of a working fluid containing a UV-reactive chemical marker to light having wavelengths in the range of about 10-400 nm, thereby causing the chemical marker to generate a signal. The signal can be detected via a sensor system and compared to a reference signal that is associated with an authentic working fluid. An output may be generated to indicate whether the working fluid is the authentic working fluid.