Plasma physics is a very multidisciplinary because we have to use a lot of fields such as electromagnetism, chemistry, thermodynamics, electrical sciences, atomic and molecular physics, fluid mechanics, vacuum technology... If we add to the above also plasma diagnostics, we also have to consider optics, mechanics, optronics and electronics. few years now, plasma physics has entered the field of medicine. This evolution is so important that some scientists compare the plasma medicine application to the development of the laser technology a few decades ago. This report contains the results, analysis and discussion of a diagnostics study of an Argon and Helium RF atmospheric pressure plasma jet. We present measurements of dissipated power in the plasma, the emission spectroscope and the gas temperature of the jet. In order to create more reactive species which could be beneficial for biomedical applications, we add small amounts of Nitrogen or Oxygen to the jet. The influences of these mixtures are investigated and the results are discussed. To approach to the future applications conditions, some tests are performed during which the plasma interacts with saline solutions or distilled water and investigated. This leads us to compare all the results together in order to get some conclusions about the power, gas temperature and emissions.