Separation of Plant Pigment by Paper Chromatography- myassignmenthelp

Question: Discuss about theSeparation of Plant Pigment by Paper Chromatography. Answer: Plants have molecules that have the ability to absorb certain wavelength of light and reflect others. These colored molecules found in plants are called pigments, the color being imparted by virtue of selective absorption of light waves. Molecules contain electrons that can absorb a particular amount of energy and move to the next higher energy level from their resting state. Light waves having that optimum level of energy within them get absorbed by a molecule and all other light waves are reflected back (Bassham 2015). Same phenomenon occurs in case of plants pigments. The gained energy is released or transferred in various forms to return back to its resting state. In plants that energy is utilized during photosynthesis to convert the solar energy into chemical energy of glucose or other carbohydrates. Some of the different kinds of pigments found in pants are Chlorophyll, Carotenoid and Xanthophyll. Apart from photosynthesis, the vibrant colors of pigments of attract insects whic h eventually help in pollination. Chlorophyll is the main pigment found in all plants. It can be of different types- chlorophyll a, b, c and d. Chlorophyll a absorbs light of wavelengths 430 nm (blue) and 662nm (red), strongly reflecting green light. Carotenoids are accessory pigments absorbing light of wavelength between 460nm to 550nm. Other pigments do not absorb light as efficiently as the two already mentioned (Tanaka, Sasaki and Ohmiya 2008). Chromatography is one of the most widely used methods in separation science. It can separate molecules based on their solubility in a particular solvent and identify them using predefined standards. It has been classified into several types based on the phases used and the separation mechanisms. The most common types of techniques are Paper Chromatography, Column Chromatography, This Layer Chromatography, Gas Chromatography, Thin Layer Chromatography, and Affinity Chromatography and so on. Paper Chromatography have been widely used to separate plant pigment. The basic principle is the pigment extracts are being places on the paper, the stationary phase and placed in developing chamber with an appropriate solvent. The solvent binds with the pigments and travels different lengths based on their solubility in the solvent. Most soluble pigments travel the farthest. Each pigment has a standard distance that it travels (Block, Le Strange and Zweig 2013). The ratio of the distance travelled by a pigment to that of the solvent font is known as the Rf value. The equipment required to perform a pigment separation experiment are as flows: Plant leaves, Ruler Large, test tube Cork with push pin, Chromatography paper (precut 18 cm strips), Pencil, Chromatography solvent (9:1 petroleum ether acetone), 6 ml syringe, Colored pencils, Calculator, Scissors, Plastic wrap (Ikan 2013). After extracting the pigments they are placed on the paper separately along a line drawn on it. The solvent is taken in a test tube and the paper is placed inside it carefully and left undisturbed. The pigments will rise to different heights and separate into distinct bands. The distance travelled by the solvent and the pigments are then measured and the Rf values are calculated using a calculator. The values are compared to standard values to identify the different pigment present in the mixture. References Tanaka, Y., Sasaki, N. and Ohmiya, A., 2008. Biosynthesis of plant pigments: anthocyanins, betalains and carotenoids.The Plant Journal,54(4), pp.733-749. Bassham, D.C., 2015. Plant biology: Pigments on the move.Nature,526(7575), pp.644-645. Block, R.J., Le Strange, R. and Zweig, G., 2013.Paper Chromatography: A Laboratory Manual. Elsevier. Ikan, R., 2013.Natural products: a laboratory guide. Elsevier.