Paper Chromatography Essay

Boynton, R.M. 1987. Color. In McGraw-Hill Encyclopedia of Science & Technology (Vol. 4, 165-166) McGraw-Hill, Inc.

There are two main types of chlorophyll, chlorophyll a which absorbs wavelengths of 430nm (blue) and 662 (red) and is the main photosynthetic pigment, and chlorophyll b, which doesn’t directly participate in the photosynthetic process, but is capable of donating its energy to chlorophyll a

After the serial dilutions of the red and blue dyes were taken, the molarity and absorbance for both dyes were calculated. Using the MiVi = MfVf equation, the concentrations for each value of the red and blue dye were separately calculated. Calculating absorbances calls for setting the correct wavelengths of light for each dye. In this case, the 470 nm wavelength for red dye and the 635 nm wavelength for blue dye was needed to find the maximum absorbances. The absorbance was found by blanking the colorimeter and entering the concentrations. After both values of the absorbances and concentrations were found, the values were then graphed in order to obtain the equation of the relationship between absorbance and concentration.

The image above is our chromatogram, you can see at the top the orange bands of a carotene, next are the bands of xanthophylls which are yellow. The next light green bands directly bellow the yellow is chlorophyll a, the darker green bands are chlorophyll b. In order to test absorbance of the chlorophylls they were cut out of this chromatogram submerged into acetone and then used to get an absorption spectrum as seen below.

In the beginning of this experiment, our TA added water, salt, and 75/25 hexane/acetone to spinach leaves to a blender and blended the mixture to assume equal amounts for each group and to avoid erros if each student had to do the blending. The addition of the water to the mixture allowed the it to separate into a distinct organic layer after being run in a centrifuge, which was available to be collected at the top of the centrifuge. Salt reduces solubility, which will force the organic parts of the mixture (the desired pigments for example) to separate into the organic layer at the top. Lastly, 75/25 hexane/acetone is added because this is a moderately polar solvent and will useful for both the non-polar and polar pigments present within the spinach leaves. A mixed solution of hexanes and acetone must be used because acetone is very polar, while hexane in very non-polar, and the spinach leaves contain both non-polar and polar pigments in them that are important in the extraction and for further analysis. The mixture was placed in the centrifuge so the solids in the mixture (mostly cellulose) could be separated from the liquids into separate distinct layers for further extraction and testing. In the tube, the organic substances separated into the top layer, whereas the water layer remains at the bottom of the tube below the solid layer made up of mainly cellulose.

Abstract: The purpose of this lab is to separate and identify pigments and other molecules within plant cells by a process called chromatography. We will also be measuring the rate of photosynthesis in isolated chloroplasts. Beta carotene, the most abundant carotene in plants, is carried along near the solvent front because it is very soluble in the solvent being used and because it forms no hydrogen bonds with cellulose. Xanthophyll is found further from the solvent font because it is less soluble in the solvent and has been slowed down by hydrogen bonding to the cellulose. Chlorophylls contain oxygen and nitrogen and are bound more tightly to the paper than the other pigments.

1. Paper Chromatography is a method used for the separation of colors which are also referred to as colored chemicals/substances or pigments. This method is used for experiments, to identify coloring agents and to separate out a compound into its various components.

Pigments extracted from different greens have different polarities and may be different colors. Mixed pigments can be separated using chromatography paper. Chromatography paper is able to separate mixed pigments due to their polarity and solubility. Pigments of chlorophyll a, chlorophyll b and beta carotene will be separated on chromatography paper because each has its own polarity and solubility, which results in different distance traveled up the paper. Beta carotene is non-polar so it travels the highest distance, followed by chlorophyll a. Chlorophyll b is the most polar; therefore, it travels the shortest distance. The separated pigments on the chromatography paper can be eluted in acetone and absorbance spectrum is

Chromatography is a separation technique in which the mixture to be separated is dissolved in a solvent and the resulting solution, often called the mobile phase, is then passed through or over another material, the stationary phase. The separation of the original mixture depends on how strongly each component is attracted to the stationary phase. Substances that are attracted strongly to the stationary phase will be retarded and not move alone with the mobile phase. Weakly attracted substances will move more rapidly with the mobile phase.

The purpose of this experiment was to take spinach leaves and extract the chlorophyll and carotenoid pigments by using acetone as the solvent. The chlorophyll and carotenoid pigments were extracted by using column chromography and alumina was used as the solvent. Solvents of different polarities were used, starting with the least polar, to extract the certain components from the leaves. They were then analyzed by using thin- layer chromatography.

The purpose of this lab is to determine which pigments in a plant support or effect photosynthesis, based on starch production, which wavelengths of light are involved in photosynthesis, and identify plant pigments found in a plant leaf by means of paper chromatography.

However, the photosynthetic process can be affected by different environmental factors. In the following experiment, we tested the effects that the light intensity, light wavelength and pigment had on photosynthesis. The action spectrum of photosynthesis shows which wavelength of light is the most effective using only one line. The absorption spectrum plots how much light is absorbed at different wavelengths by one or more different pigment types. Organisms have different optimal functional ranges, so it is for our benefit to discover the conditions that this process works best. If the environmental conditions of light intensity, light wavelength and pigment type are changed, then the rate of photosynthesis will increase with average light intensity and under the wavelengths of white light which will correspond to the absorption spectrum of the pigments. The null hypothesis to this would be; if the environmental conditions light intensity, light wavelength and pigment type are changed, then the rate of photosynthesis will decrease with average light intensity and under the white light which will correspond to the absorption spectrum of the pigments.

In this lab, varying wavelengths were used to test how light affects photosynthesis and respiration as a whole. The absorbance of lights from 380 nm to 720 nm of chlorophyll pigment from the Elodea sample

The next step was to place the strip of chromatography paper on a paper towel. Then dip a capillary tube into the plant pigment extract (spinach pigment extract) provided by the teacher. The tube will fill on its own. We applied the extract to the pencil line on the paper, blew the strip dry, and repeated it three to four times until the line on the paper is a dark

Chromatography Investigation Chromatography is a highly regarded technique used to separate the components of a mixture. It is based on the principle that each component possesses a unique affinity for a stationary phase and a mobile phase. The components that are more inclined to enter the mobile phase will migrate further on the chromatogram and distinguish themselves from the other components. The type of solvent used in chromatography is known to directly affect the separation of the mixture. In this experiment, thin-layer and column chromatography will be utilized to separate the numerous chlorophyll and carotenoid pigments of a spinach extract.