Spinach Lab Report

733 Words 3 Pages
Introduction Spinach is a leafy green plant that is high in vitamins. Spinach gains its green color from the pigments it contains which help the plant absorb sunlight needed for photosynthesis. The main pigments are chlorophyll a, chlorophyll b, and β-carotene. Chlorophyll presents as a green pigment and is a porphyrin while β-carotene is a red-orange pigment and a carotenoid. [1] They are both found in all pants and are sensitive to exposure to light and air. β-carotene has been used in the treatment of various diseases including prevention of certain types of cancers and cataracts. [2] Chlorophylls have also been studied in the medical field. They are thought to form complexes with cancer causing agents and thereby block the carcinogenic …show more content…
[3] For the sake of extraction, spinach is first dehydrated with 100% ethanol so that extraction is more efficient. It is then extracted using dichloromethane (DCM) and maceration. The chlorophyll and β-carotene pigments are dissolved into the organic DCM layer which is polar and does not mix with water. The solution is then washed with sodium chloride (NaCl) to draw out any remaining water left in the solution that was not dried out by the ethanol. [1] Water will move toward the more hypertonic solution and separate from the DCM extract. After successful separation of the pigments from the spinach leaves, the pigments are put into silica gel and the solvent is allowed to evaporate off so that the pigments (now in powder form) can be put through column chromatography to separate the chlorophyll and β-carotene pigments. Column chromatography is a means to divide chemical compounds from a mixture. Separation is achieved by eluting solvents through the column which hold similar properties to one or the other pigment. Chlorophyll, being a polar molecule, moves through the stationary phase of the column only when a polar mobile phase is added. Similarly, β-carotene follows the same principle with …show more content…
The column was packed differently than the lab manual suggested. The column contained a glass wool stopper, 1 cm of sand, and 15-20 grams of packed silica all suspended in pure hexane as the solvent. One the column was packed and settled, the crude product was added in. One settled, a 9:1 nonpolar mixture of hexane to ethyl acetate was used to elute the β-carotene and was collected in a pre-weighted Erlenmeyer flask. Next, a 1:1 polar mixture of hexane and ethyl acetate was added to elute the chlorophyll which was also collected in a pre-weighted Erlenmeyer flask. The products were then evaporated with a hot air gun and left overnight to evaporate completely. When the solvent was fully evaporated, the flasks were weighted and calculations of mass and yield were

Related Documents