Extraction chlorophylls

Commercial food grade water-soluble Cu-chlorophyllin is the most notable among these preparations. Copper chlorophyllins are produced from crude natural chlorophyll extracts followed by the hydrolysis of the phytyl and methyl esters, cleavage of the cyclopentanone (E) ring in dilute alkali, and the replacement of magnesium by copper. ... 

Moreover chlorophyll extract purity can be assessed by examining fluorescence since it is more sensitive than absorbance. 

B 2. Explain the chlorophyll extraction procedure in chemical terms. Why is acetone effective in the extraction How could the experiment be modified to increase the yield of chlorophyll extraction ... 

As with the other porphyrins, the chlorophylls have distinctive visible absorption spectra. Since their role is to absorb visible radiation, their absorption spectra are of vital importance. Chlorophyll extracted from plants and dissolved in a polar solvent absorbs near 660 nm however, in the plant the maximum absorption is nearer 680 nm. The significance of this red shift in terms of molecular aggregation and the relation to photosynthesis has been discussed by Katz148 but lies outside the scope of this chapter. 

To obtain clear solutions, the extracts are either filtered or centrifuged and the residues reextracted with the same solvents (108). Another possibility is to transfer the chlorophylls from the acetone phase into an ether phase by adding sodium chloride (114) or sodium sulfate (93). More recently acetone extracts were purified and fractionated with C18 solid-phase extraction cartridges, and dephytylated pigments were eluted with 70% acetone and phytylated pigments with 90% acetone (115). Often a concentrating of the pigment solution with a rota-evaporator under vacuum is necessary before analysis. Chlorophyll extracts should be analyzed as soon as possible, but if they have to be stored they must be kept in the cold and dark (107). 

Chlorophyll extracts electrons from water one at a time. To generate oxygen from water, it must absorb four photons and lose four electrons in succession, each time drawing an electron from one of two water molecules.3 The overall water-splitting reaction is ... 

Only in the final stage is oxygen released. The rate at which chlorophyll extracts electrons depends on how quickly the photons are absorbed. As the successive steps cannot take place instantly, a series of potentially reactive free-radical intermediates must be produced, if only transiently. 

Chlorophyll extraction and spectroscopic measurements are applied to assess the degree of integrity of the chlorophyll in photobiontic cells in lichens. The extraction of chlorophyll is usually performed by dimethyl sulfoxide (DMSO) or acetone. The exposure of lichen thalli to chemical pollutants, either under controlled conditions or under natural conditions in the presence of air pollutants, leads in many cases to a degradation of chlorophyll. 

Dedicated pre-screens for protectants would best be developed with in vitro cultures of the crop to be protected. This can be problematic with herbicides which affect photosynthesis when green photosynthetic cultures are not available. A pre-screen for protectants against diquat was set up using a duckweed mini-plant system (Figure 3). Such a system has the advantage that potential protectants can be seen by their effects on growth and color. They can also be quantifled by measuring 002 fixation or by chlorophyll extraction (2f). 

Hosikian A, Lim S, Halim R, Danquah MK. Chlorophyll extraction from microalgae a review on the process engineering aspects. IntJ Chem Eng 2010 2010 1. 

In general, procedures used for these studies involve the treatment of soil plots and the removal of samples from treated and control plots over a specified time frame after treatment. The algal population in the sample is then estimated, most frequently by a soil dilution technique (Fields and Hemphill 1968, Cullimore and McCann 1977, Calle 1970, Huge 1970). Pantera, however, used chlorophyll extraction as an index of population size in soil samples pre-enriched with a nutrient medium (1970). 

Experiments have been reported elsewhere in which chlorophyll, as well as other alcohol-soluble material, was removed from chloroplast fragments, and a light-dependent reduction of oxidized glutathione, via the TPN-linked yeast glutathione reductase, was observed upon recombination of the chlorophyll extract with the colorless fraction (374a). 

Porra, R.J., Recent advances and re-assessments in chlorophyll extraction and assay procedures for terrestrial, aquatic, and marine organisms, including recalcitrant algae, in Chlorophylls, Scheer, H., Ed., CRC Press LLC, Boca Raton, FL, 1991, p. 31. 

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