The molar extinction coefficients of pheophorbide a, methyl pheophorbide a, and pheophytin a are identical within experimental error. A similar situation holds for pyropheophorbide a and its methyl ester.Pheophorbide a and pyropheophorbide a are adsorbed on glass from solution in ether and chloroform but not from solution in acetone or dioxane.It is recommended acetone be used as the solvent for the quantitation of pheophorbide a and pyropheophorbide a.