7.10: Pipette Column Chromatography

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Table 7.10: Procedural summary for pipette column chromatography.

Wedge a bit of cotton into the bottom of a pipette. Use a scooping method to fill silica or alumina to 2-2.5 inches high.	Add a \(0.5 \: \text{cm}\) layer of sand.	Add eluent to the column and apply pressure with a pipette bulb to force eluent through the column to completely wet it.	Remember to break the seal before letting go of the pipette bulb, or suction will ruin the column. Refill the column with eluent as necessary.

Adjust the eluent level to the sand layer, and then delicately add the sample. Use pressure to push the eluent down onto the silica/alumina layer. Rinse with one portion of eluent and push the solvent onto the column.	Fill the pipette with eluent and apply pressure to elute the column. Collect liquid into test tubes. Always keep the white column section wet (refill whenever the eluent level nears the sand layer).	Switch test tubes periodically (perhaps when they are \(1 \: \text{cm}\) high in small test tubes) to collect different fractions.	Keep fractions organized in a test tube rack in the order they are eluted. Use TLC to determine the purity of the fractions, and combine appropriate fractions. Remove the solvent with the rotary evaporator.