Figure 4

The absorption spectra of a mixture of H₂O₂, NO₂⁻ and NO3⁻ match the absorption spectra of plasma-activated PBS(Ca²⁺/Mg²⁺).

Absorption spectra between 200 and 300 nm of different concentrations of H₂O₂ (A), NO₂⁻ (B) and NO₃⁻ (C) prepared in PBS(Ca²⁺/Mg²⁺). The data are the mean ± SD of 5 (H₂O₂) and 4 (NO₃⁻ and NO₂⁻) independent experiments. (D) Absorption spectra of a mixture of 800 μM H₂O₂, 800 μM NO₂⁻ and 200 μM NO₃⁻ prepared in PBS(Ca²⁺/Mg²⁺). The data are the mean ± SD of 4 independent experiments. (E) 500 μl of PBS(Ca²⁺/Mg²⁺) were exposed to He plasma at a flow rate of 50 sccm for 2 min and the absorption spectra were recorded between 200 and 300 nm. The data are the mean ± SD of 3 independent experiments. (F) Comparison between the absorption spectra of a mixture of 800 μM H₂O₂, 800 μM NO₂⁻ and 200 μM NO₃⁻ (curves shown in panel D) and the absorption spectra of plasma-activated PBS(Ca²⁺/Mg²⁺) (curves shown in panel E). As indicated in the panels D, E and F, the solutions containing H₂O₂, NO₂⁻ and NO₃⁻ or plasma-activated PBS(Ca²⁺/Mg²⁺) were diluted 2x, 4x, or 8x in PBS(Ca²⁺/Mg²⁺) before the spectroscopic measurements.