The following equations are proposed for correct calculations of pigment concentrations (E, phycoerythrin; C, phycocyanin, mg ml-1 in red algal crude extracts, from absorption measurements:
E=[(A564 - A592) - (A455-A592) 0.20] 0.12,
C=[A618 - A645) - (A592-A645) 0.15] 0.15
These equations are shown to yield results that are not affected by the concentration of interfering components. Fluorometry is also shown to be suitable for phycoerythrin measurements (with much higher sensitivity) in the same type of extracts.