The specific absorption coefficients of chlorophyllide a and pheophorbide a in 90% acetone, and comments on the fluorometric determination of chlorophyll and pheopigments1

Chromatographically pure chlorophyllide a and pheophorbide a were obtained from cultured algae by thin layer chromatography. After 7–10 cell divisions in the presence of 14 C, the cells (and all inclusions) used for the study were uniformally labeled. Measurement of the optical densities and radioactivities of chlorophyll a and these other pigments permits calculation of the specific absorption coefficients for the latter. The specific absorption coefficients measured were: pheophytin a −49.5; chlorophyllide a −128; and pheophorbide a −69.8.