Singlet oxygen generation by Photofrin in homogeneous and light-scattering media

The singlet oxygen quantum yield (phi delta) for Photofrin solubilized by Triton X-100 was measured in homogeneous and light-scattering media using the photosensitized inactivation of lysozyme as an internal actinometer. Higher values of phi delta at 630 nm than at 514 nm are attributed to the formation of a far-red-absorbing photosensitizing photoproduct.