Transient absorption spectroscopy has been used to elucidate the UV-A induc
ed photodynamics of quinacrine. Following excitation of quinacrine in a pH
7.2 buffer solution at 395 nm, the excited molecule ejects an electron into
the surrounding aqueous solution. The quantum efficiency for solvated elec
tron formation at this excitation wavelength is determined to be in the ran
ge of 0.20-0.40. These results provide a simple mechanism that accounts for
the generation of superoxide (O-2(-)) following UV excitation of quinacrin
e in aqueous solution.