## 2 Results
Changes in the redox potential of water and NaCl solutions under the influence of a magnetic field are shown in Figure 4. The redox potential of deionized water and NaCl solutions increased with increased magnetic field strength. With an increase in the concentration of ions in the solution, the relative increase in the redox potential was also slightly higher. Thus, if the relative increase in the redox potential of water was \(\sim\)4 mV/T, then for a 1 M NaCl solution it was 7 mV/T. An increase in the number of charge carriers in the solution can lead to a more pronounced change in the redox potential of the solution when exposed to a magnetic field. The redox potential of deionized water and aqueous solutions is usually associated with the concentration of dissolved molecular oxygen [32]. In this regard, we investigated the effect of the magnetic field on the concentration of molecular oxygen dissolved in deionized water and NaCl solutions (Figure 5). No changes were observed in the concentration of molecular oxygen in deionized water under the action of magnetic fields of different strengths. However, there was a tendency towards a decrease in the concentration of dissolved molecular oxygen in NaCl solutions with an increase in the magnetic field induction. Moreover, the higher the concentration of ions in the solution, the more pronounced the degassing of the solution became. Thus, an increase in the redox potential cannot be explained by an increase in the concentration of molecular oxygen. Figure 4: Change in the redox potential of water and NaCl solutions depending on magnetic field induction. Data are presented as means and standard errors of the mean (n = 3–6). Figure 3: Change in pH value depending on magnetic field strength in water and NaCl solutions. Data are presented as means and standard errors of the mean (n = 3–6). In addition to the role of molecular oxygen, the generation of reactive oxygen species can also lead to an increase in redox potential. The most stable type of reactive oxygen species is hydrogen peroxide. The influence of magnetic fields on the generation of hydrogen peroxide in water and aqueous solutions of NaCl was investigated (Figure 6). It was found that under the influence of a magnetic field, the generation of hydrogen peroxide occurs both in deionized water and in aqueous salt solutions, depending on the magnetic field strength. The relative increase in the concentration of generated hydrogen peroxide in water was 1 nM/T. With an increase in the salt concentration, the relative increase in the concentration of generated hydrogen peroxide was higher, so in a 1 M NaCl solution it reached almost 2.5 nM/T. At the same time, with an increase in the concentration of salt in water, the base level of hydrogen peroxide slightly increased. Thus, under the influence of a magnetic field, an increase in the number of charge carriers in the solution leads to a relative increase in the concentration of generated hydrogen peroxide. We found that it is often necessary to stir solutions during measurements in order to obtain stable results, including using a magnetic stirrer. Therefore, the various methods of stirring or mixing aqueous solutions during the dilution process may affect their basic physicochemical properties. To clarify this technicality, a series of experiments was carried out in which the effect of flow-mixing solutions using a microfluidic system was investigated. Figure 5: Changes in the concentration of molecular oxygen dissolved in water or NaCl solutions depending on magnetic field strength. Data are presented as means and standard errors of the mean (n = 3–6). Figure 6: Change in the concentration of hydrogen peroxide in water and aqueous NaCl solutions depending on the magnetic field strength. Data are presented as means and standard errors of the mean (n = 3–6). In order to take into account the impact of ionic strength, both NaCl solutions and deionized water were mixed.