Fluorometric determination of chlorophylls

The method described here is based on the use of the Tumra fluorometer as suggested by C.S. Yentsch and D.W. Menzel Deep ea Res., 10 221, 1963) and subsequently investigated by Hohn-Hansen et al (J. Conseil, Consol Perm. Intern. Exploration Mer, 30 3, 1965). The method is not so accurate as the ectrophoto-metric approach but has the convenience of speed and the requirement of much smaller sanqile volumes for a given sensitivity. Only chlorophyll a is determined. 

The limit of detection will depend upon the volume of water filtered and the sensitivity of the fluorometer. IMth a 2-liter sample about 0.01 mg chlorophyll i/m should be detectable with surety. Hie predsion is very much dependent on the amount of pigment being determined but P see NOTE ON statistical limits) is bettor than 8% of any value of chlorophyll a exceeding 0.5 mg/nP. 

Extracts obtained as described in IV.3.I are measured fluorometrically with the Turner fluorometer. 

See 1V.3.I,C but only glass filters should be used. The Turner fluorometer is fitted with the high sensitivity door, F.4T4-BL lamp, Wratten 47B or Coming CS.5-60 filter for the excitation light and Corning CS.2-64 filto for the emitted light. 

The extracts from 0.25-2 liters, obtained exactly as described in IV. 3.1,F. 1-5, but using only 10.0 ml of 90% acetone, are measured in a Turner fluorometer with the scale zeroed for each door opening against a tube of 90% acetone. Provided that phaeo-pigments are absent  

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Gibbs, C. E, 1979. Chlorophyll b interference in the fluorometric determination of chlorophyll a and phaeo-pigments . Australian Journal of Marine and Freshwater Research, 30, 597-606. 

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