Spinach pigments chromatography
Since the consumer prefers yellow butter and margarinethe dairy companies used to add a dye called Butter Yellow to white butter.
Concentrate the organic layer by using a rotoevaporator. Change to test tube 2 to collect the yellow band. Using a pipette, add 10 mL leaf extract to the top of the column.
Place the clean, dry test tube 1 under the column to collect the solvent.
Continue the addition of hexane until you get the yellow band near the bottom of the column. Be careful : Never let silica to dry in the column.
Draw a picture of your TLC plate as it appears next to the data table. Include the elution solvent system. Use a piece of stiff wire or the tip of another pipet to push the cotton in place.
Carotenoids are part of a larger collection of plant-derived compounds called terpenes. The third from above dark green band represents chlorophyll a.
Rf values for spinach pigments
When the yellow band reaches the bottom of the column, collect layer in a test tube. Separation of the sample is achieved. Column Chromatography Weigh 1. This is your extract. Result The topmost orange yellow band of pigments in the separation corresponds to carotene. You should spot the extract you saved as well as fraction 2 yellow and fraction 4 green. Carotenoids are part of a larger collection of plant-derived compounds called terpenes. Grind the leaves until the pieces are too small to be seen and then filter the pigment extract if needed. Seal the flask and place it temporarily in your lab drawer. These naturally occurring compounds contain 10, 15, 20, 25, 30 and 40 carbon atoms,which suggest that there is a compound with five carbon atoms that serves as theirbuilding block. For 'flash' column chromatography, moderate air pressure is used to pushthe solvent through the column. What would happen to the Rf value of the pigments if you were to increase the relative concentration of acetone in the developing solvent?
Mckay, P. Purpose: To separate plant pigments from spinach leaves using column chromatography.
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