These videos show bottom and side views of the treatment by a He/O2 plasma jet of a solution containing ultra-pure water, potassium iodide and starch. As the plasma reaches the liquid, a purple filament characteristic of the triiodide ion/starch complex appears. This complex is formed by the reaction between iodide ion and a reactive oxygen and nitrogen species (RONS) such as ozone, hydrogen peroxide, hydroxide ion, nitric oxyde or nitrate. Therefore, the formation of these RONS in the liquid phase is temporally and spatially quantified.