Extinction Coefficients of Chlorophyll a and b in N,N-Dimethylformamide and 80% Acetone 1

Abstract

We found inconsistencies in the commonly used data for chlorophyll analysis in 80% acetone. Recently developed extinction coefficients for chlorophyll b in N,N-dimethylformamide (DMF) based on values from 80% acetone are low as a result of these inconsistencies. We determined extinction coefficients of chlorophyll a (Chl a) and chlorophyll b (Chl b) in DMF for wavelengths of 618 to 665 nanometers. The simultaneous equations necessary for quantifying Chl a, Chl b, or total Chl in DMF in the absence of other chlorophyllous pigments are: Chl a = 12.70A  _664.5 - 2.79A  ₆₄₇; Chl b = 20.70 A  ₆₄₇ - 4.62A  _664.5; total Chl = 17.90A  ₆₄₇ + 8.08A  _664.5, where A = absorbance in 1.00 centimeter cuvettes and Chl = milligrams per liter.

N,N-Dimethylformamide is a very convenient solvent for Chl extraction since it is effective on intact plant parts and Chl is quite stable in DMF. There was no difference in the amount of Chl extracted when plant tissue was stored for 1 or 3 days at three temperatures, with or without solvent added.

1

Scientific Journal Series, paper no. 14,107, Minnesota Agricultural Experiment Station.