Characterization of Low-Temperature Microwave Plasma Treatment With and Without UV Light for Disinfection

Chemical characteristics and bactericidal properties of two low-temperature atmospheric-pressure Ar plasma devices are investigated: one of them with UV and the other with almost no UV on treated samples. The control of the UV radiation is achieved by two nozzles. One has a straight shape, and the other has a 90 degrees-bent. The bent nozzle blocks the light produced inside the torch, whilst allowing the plasma gas to reach the samples. The use of the straight nozzle allows the treatment by both the plasma gas and UV. We demonstrate that even an almost UV-free plasma treatment has bactericidal properties. Our measurements suggest that reactive species represent the main bactericidal factor of our low-temperature plasma.