title: Spectrophotometric method of controlled pheophytinization for the determination of both chlorophylls and pheophytins in plant extracts.
abstract: Conventional spectrophotometric methods of chlorophyll (Chl) measurement with double-wavelength readings of absorbances corresponding to the peak values of both Chl a and Chl b are usable only is pheophytins (Pheo) are absent in the pigment extract. We present here a kinetic method of controlled phenophytinization of the Chl present in acetone/water (90/10, v/v) exctracts that allows the measurement of both Chl a and b, as well as of the initial Pheo preexisting in the plant material at the moment of the extraction. This method gives better accuracy in Chl b determination than conventional methods, particularly when Chl a/Chl b ratios are greater than 5. Examples are given illustrating the usefulness of this method.
mesh_terms: D002734:Chlorophyll / Q000031:analogs & derivatives* / Q000032:analysis*; D005056:Euglena gracilis / Q000032:analysis; D007700:Kinetics; D008433:Mathematics; D010674:Pheophytins / Q000032:analysis*; D010936:Plant Extracts / Q000032:analysis*; D013053:Spectrophotometry / Q000379:methods
chemical_list: D010674:Pheophytins; D010936:Plant Extracts; D002734:Chlorophyll