Validation of colorimetric assays for hydrogen peroxide, nitrate and nitrite ions in complex plasma-treated water solutions

Liquids treated with cold plasma emerged as ‘redox drugs’ in biomedicine, as sources of reactive oxygen and nitrogen species targeting cellular functions, including wound healing and cancer progression. The use of cell culture media as starting liquid, however, challenges the identification of plasma-generated chemistry, limited by the presence of many reactive species and organic compounds. Available detection methods need, therefore, to be confirmed in these liquids to avoid inaccurate results. In this research, robustness, linearity, accuracy and specificity of three colorimetric assays are investigated to detect H2O2, NO2− and NO3−, predominant plasma-induced products. The results clearly highlight the presence of some factors affecting the detection in cell culture media like high concentrations of chlorides found interfering with the detection of NO3− in the medium.