Chlorophyll b Interference in the Fluorometric Determination of Chlorophyll a and 'Phaeo-Pigments'

1979 ◽  
Vol 30 (5) ◽  
pp. 597 ◽  
Author(s):  
CF Gibbs
Keyword(s):  
Chlorophyll A ◽  
Quantitative Estimate ◽  
Aqueous Acetone ◽  
Chlorophyll B ◽  
Fluorometric Determination ◽  
Chlorophyll A Concentration ◽  
Marine Samples ◽  
Water Ratio

A quantitative estimate was made of the interference by chlorophyll b in the fluorometric determination of chlorophyll a using an Aminco-Bowman spectrofluorometer. The undegraded (or 'living') chlorophyll a concentration was underestimated by an amount equal to the concentration of chlorophyll b present. The value for chlorophyll a uncorrected for phaeophytin was increased by 30% of the chlorophyll b concentration. The acetone to water ratio was found to affect the acidification factor only at aqueous acetone concentrations above 90%. The need for standardization of solvent and wavelengths is discussed, and the implications of chlorophyll b occurring in marine samples are considered.

Triplet-State Electron Spin Resonance of Chlorophyll a and b Molecules and Complexes in PMMA and MTHF. I: Experimental Determination of Fine-Structure and Rate Constants

1978 ◽  
Vol 33 (1) ◽  
pp. 83-93 ◽  
Author(s):  
W. Hagele ◽  
D. Schmid ◽  
H. C. Wolf
Keyword(s):  
Triplet State ◽  
Chlorophyll A ◽  
Rate Constants ◽  
Resonance Field ◽  
Zero Field ◽  
Chlorophyll B ◽  
Low Concentrations ◽  
Spin Resonance ◽  
Chlorophyll A And B

The triplet state zero-field splittings and the rate constants for the population and depopulation of the triplet spin sublevels have been investigated for chlorophyll a and chlorophyll b in polymethylmethacrylate (PMMA) and methyltetrahydrofurane (MTHF) as a function of the concentration. In PMMA both chlorophyll a and chlorophyll b yielded only one ESR spectrum in the entire range of concentration which could be covered (1.5 × 10-5 - 1 × 10-3 mole/1). In MTHF the results were more complicated. At low concentrations (up to 103 mole/1) only one spectrum was observed, at higher concentrations additional spectra were detectable (all together two for chlorophyll a and five for chlorophyll b at 10-1 mole/1). The assignment of these spectra was facilitated by observing the "triplet resonance-field identity" which connects the resonancefield strengths for the canonical orientations of one particular species. Furthermore, the rate constants for some of these species could be determined.

scholarly journals Non-destructive measurement of chlorophyll b:a ratios and identification of photosynthetic pathways in grasses by reflectance spectroscopy

2009 ◽  
Vol 36 (11) ◽  
pp. 857 ◽  
Author(s):  
Katharina Siebke ◽  
Marilyn C. Ball
Keyword(s):  
Chlorophyll A ◽  
Reflectance Spectra ◽  
Grass Species ◽  
Chlorophyll B ◽  
Hordeum Vulgare L ◽  
Chlorophylls A And B ◽  
Fluorescence Characteristics ◽  
Destructive Measurement ◽  
Non Destructive

Equations for non-destructive determination of chlorophyll b : a ratios in grasses were developed from reflectance spectra of intact leaves of barley (Hordeum vulgare L.) and two barley mutants: clorina f2, which lacks chlorophyll b and clorina f104, which has a low chlorophyll b content. These plants enabled separation of effects of chlorophyll composition on reflectance spectra due to differential light absorption by chlorophylls a and b and to measure the effects of chlorophyll b on the contribution of fluorescence emitted by chlorophyll a to the reflectance spectra. Indices developed from these data were then tested on growth chamber-grown leaves from six C3 and 17 C4 grass species (7 NAD-ME and 10 NADP-ME subtypes). We used the chlorophyll b : a ratio because the data were less skewed than the chlorophyll a : b ratio. The best index for determination of the chlorophyll b : a ratio utilised wavelengths affected by chlorophyll absorbance: [R626 – 0.5 (R603 + R647)]/[R552– R626]. The chlorophyll b : a ratio was significantly lower in the C4 than C3 grasses, but was not sufficient in itself to separate these two functional groups. However, because of differences in fluorescence characteristics, C3 and C4 species could be distinguished by an index based on wavelengths affected by chlorophyll fluorescence: [R696 to 709/R545 to 567].

Micellar enhanced spectrofluorometric determination of chlorophyll a and chlorophyll b in fresh waters☆

Talanta ◽  
1992 ◽  
Vol 39 (3) ◽  
pp. 195-200 ◽  
Author(s):  
Jose J. Santana ◽  
MaryAnn Gunshefski ◽  
James D. Winefordner
Keyword(s):  
Chlorophyll A ◽  
Chlorophyll B ◽  
Fresh Waters ◽  
Spectrofluorometric Determination
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