Na. Welschmeyer, FLUOROMETRIC ANALYSIS OF CHLOROPHYLL-A IN THE PRESENCE OF CHLOROPHYLL-B AND PHEOPIGMENTS, Limnology and oceanography, 39(8), 1994, pp. 1985-1992
A fluorometric method is described which provides sensitive measuremen
ts of extracted chlorophyll a free from the errors associated with con
ventional acidification techniques. Fluorometric optical configuration
s were optimized to produce maximum sensitivity to Chl a while maintai
ning desensitized responses from both Chl b and pheopigments. Under th
e most extreme Chl b :Chl a ratio likely to occur in nature (1 : 1 mol
ar), the new method results in only a 10% overestimate of the true Chl
a value, while estimates from older acidification methods are 2.5-fol
d low. Under conditions of high pheopigment concentrations (pheo a : C
hl a = 1 : 1 molar), the new method provides Chl a estimates that are
equivalent to those determined from the acidification technique. The n
ew simple method requires a single fluorescence determination and prov
ides adequate sensitivity for small sample sizes (<200 ml) even in the
most oligotrophic marine and freshwater environments.