where 𝑟 is the rate of DPBF bleaching in solution of the photosensitizer (PS), 𝐴 is the PS absorbance in the region of illumination, and index 0 represents reference PS (we used riboflavine with 𝜑 ∆ 0 = 0.52 in CH2Cl2). The value of the singlet oxygen quantum yield of riboflavin in methylene chloride was not calculated, so we measured and calculated it according to the method described above, using riboflavin in methanol as a standard ( 𝜑 ∆ 0 = 0.74) . The data processing procedure was performed as described earlier .