Wavelength dependence of bilirubin photoreactivity

The rates and products of the self-sensitized photoreactions of bilirubin IXα vary with excitation wavelength, solvent and the presence or absence of oxygen. Radical or Type I photooxidation reactions of bilirubin are implicated in degassed chloroform or methanol. Quantum yields for the disappearance of bilirubin vary from 10^?2 to 10^?4 with excitation wavelengths of 440, 340 and 280 nm and with the higher quantum yield generally appearing in chloroform solvent and/or excitation at 280 nm. Bilirubin is stable in degassed chloroform to irradiation at 440 nm.