FA13 CHEM 225 Exp8 Column Chromatography_001

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Unformatted text preview: ry important step. CAUTION: As stated previously, the column bed should NEVER be allowed to dry. Remember to close the stopcock when necessary to prevent the top of the solvent from draining below the top of the alumina. Separation. Add approximately 10 mL of fresh petroleum ether to the top of the column bed, open the stopcock, and collect the eluent in a small beaker. Monitor progress of the chromatography by determining when the first compound starts and finished eluting from the column. Monitoring may be achieved by collecting a drop or two of eluent on a watchglass after every 2-3 mL that elutes from the column. When the solvent evaporates, any white solid present will be visible on the watchglass. You can determine when all of the white solid has been eluted using this technique. Addition of more solvent may be required (only add ~5 mL at a time). Most of the white solid should elute with a volume of 10-20 mL of petroleum ether, and slow movement of a yellow band down (but not completely through) the column should occur. Use petro...
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This document was uploaded on 01/16/2014.

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