Investigation of the Photosensitizing Action of Oxygen Dissolved in Aerated Aqueous Media and Excited by Laser Radiation at 1070 and 1273 nm

The rates of chemical trapping of singlet oxygen were studied in aerated water, EtOH, and deuterium oxide upon direct excitation of oxygen molecules by radiation of diode and fiber lasers corresponding to the fundamental (1273 nm) and vibrational (1070 nm) absorption bands of oxygen molecules. 1,3-Diphenylisobenzofuran, which was solubilized in aqueous systems by adding sodium dodecyl sulfate (0.05 M), was used as a trap. The quantum efficiency of the trap oxygenation in aerated alcohol and aqueous systems with laser excitation at 1070 nm was established to be two orders of magnitude less than with excitation of the main maximum at 1273 nm, just as in recently studied organic media. The significance of these data for the use of IR lasers in phototherapy was discussed.