Pigments Chlorophyll and Carotenoids

Photosynthetic pigments, chlorophylls, and carotenoids have a clear hydro-phobic character and are usually analyzed by C18-reversed-phase (RP) columns. A C30-RP appeared on the market. The C30-RP is particularly efficient in the separation of carotenoids because the interactions of the pigments and the stationary phase are maximized by the similar size. With this phase, many cis isomers of the same carotenoid are separated from each other (Emenhiser et al., 1995 Lacker et al., 1999 Sharpless et al., 1996). This C30-RP has been successfully applied to the determination of saponified carotenoids in orange juice (Rousseff et al., 1996). However, when a mixture is complex, coelutions may become rapidly limiting and less selective stationary phases, such as the C18-RP, are therefore preferably... 

Sestak, Z., Paper chromatography of chloroplast pigments (chlorophylls and carotenoids), Part 3, Photosynthetica, 14, 239, 1980. 

The breakthrough experiment came in 1906, although hardly anyone noticed until decades later—and then, as they say, the rest is history. At that time, the Italian-Russian botanist, Mikhail Tsvet (1872-1919), was trying to separate the plant pigments, chlorophylls and carotenoids, by adsorbing them from a petroleum ether solution onto a solid material. Let us read his own words as he describes his discovery [14] ... 

Substituted pyridazinones were developed as potential photosynthetic electron transport inhibitors. For this action, they have I50 activities in the range 10" -10" It was soon discovered, however, that many of these compounds (Figure 3.6) also reduced the formation of thylakoid pigments, chlorophylls, and carotenoids. In each case, the mechanism of phytotoxicity was found to vary. In some cases, there was evidence for metabolism of the pyridazinone to a more herbicidal metabolite while in others the destruction of photosynthetic function was due to an inhibition of carotenoid (and chlorophyll) synthesis. ... 

Gross, J., Chlorophylls, in Pigments in Vegetables Chlorophylls and Carotenoids, Gross, J., Ed., Van Nostrand Reinhold, New York, 1991, 2. 

Lichtenhaler, H.K., Chlorophylls and carotenoids pigments of photosynthetic biomembranes, Meth. EnzymoL, 148, 350, 1987. 

Gross, J., Chlorophyll and carotenoid pigments of pigment of grapes (Vitis vinifera L.), Gartenbauwiss, 49, 180, 1984. 

Mantoura, R.F.C. and Llewellyn, C.A., The rapid determination of algal chlorophyll and carotenoid pigments and their breakdown products in natural waters by reversed-phase high-performance liquid chromatography, A a/. Chim. Acta, 151, 297, 1983. 

Schoefs, B., Chlorophyll and carotenoid analysis in food products. Properties of the pigments and methods of analysis. Trends Food Sci. Technol, 13, 361, 2002. 

When light from all three channels excites the fluorescence of crystalline individual compounds such as allelochemicals flavonoids quercetin and rutin or pigments of plant cells - azulene, chlorophyll and carotenoids fluoresce in different regions of the spectra in yellow and red or blue, red and yellow-orange, respectively (Fig. 7). It compares the light emission of the substances within cellular structures. 

Gross J. 1982c. Chlorophyll and carotenoid pigments in Ribes fruits. Sci Hort 18 131—136. 

H.W. Higgins and DJ. Mackey, Algal class abundances, estimated from chlorophyll and carotenoid pigments, in the western Equatorial Pacific under El Nino and non-El Nino conditions. Deep Sea Res. 47 (2000) 1461-1483. 

Gross J (1991) Pigments in vegetables chlorophylls and carotenoids. Van Nostand Reinhold, New York, NY... 

Many of the colors associated with higher plants (green leaves in the spring and summer, yellow or red leaves in the fall, the orange color of carrots, some colors in flower petals) are due to the presence of pigment molecules such as chlorophylls and carotenoids. In this experiment a mixture of these pigments will be isolated by solvent extraction of plant tissue, separated by chromatography, and the components identified by visible spectrophotometry. 

The intense colors of the chlorophylls and carotenoids make them ideal candidates for absorption spectroscopy studies (Tan and Soderstrom, 1989). In fact, each plant pigment studied in this experiment has a unique visible spectrum that can provide a positive identification. As shown in Figure E8.3, chlorophylls a and b have absorption maxima in the 600-675 and... 

In order to determine the chlorophyll and carotenoid content of your extract, you must measure the absorbance at several wavelengths, 661.6, 644.8, and 470 nm. If you are using a single-beam spectrophotometer, use a cuvette of acetone to zero the instrument at each wavelength. A double-beam instrument should have a cuvette of acetone in the reference beam and the acetone extract solution in the sample beam. If desired, it is instructive to obtain a complete spectrum of the extract in the range 400-700 nm. This can be compared to the spectrum obtained for each of the individual pigments in part D. 

B 2. Study the structures of the chlorophylls and carotenoids and predict the relative polarity of each set of pigments below. List each set in order of increasing polarity. 

H. Lichtenthaler, in Methods in Enzymology, Vol. 148, L. Packer and R. Douce, Editors (1987), Academic Press (New York), pp. 350-382, Chlorophylls and Carotenoids Pigments of Photosynthetic Biomembranes. ... 

---