Column Chromatography Lab Report

Experiment #7: Column Chromatography of Food Dye
Arianne Jan D. Tuozo
Mr. Carlos Edward B. Santos
October 12, 2015
Abstract
Column chromatography is the separation of mixture’s components through a column. Before proceeding with the column chromatography itself, a proper solvent system must be chosen among the different solvents. The green colored food dye is the mixture whose components are separated. The ammonia: 1-butanol (1:1) solvent was the appropriate solvent to use for the column chromatography of food dye because it exhibited the properties of a good solvent system. A total 8 colored eluents were collected. The eluents had colors of pink, dark red, dark blue, dark green, light green, yellow, orange and light yellow respectively and

This experiment aims to separate the components of the green colored food dye and get the TLC profile of each eluent collected.
III. Experimental Procedure
Before starting with the column chromatography for food dye, the right solvent must be chosen between 2-butanol with acetic acid, ammonia in butanol, 1 part 1-butanol 1 part acetic acid, and 2 parts methanol 1 part water. In choosing the appropriate solvent for column chromatography, the solvent system must give a TLC profile wherein most of the spots are well separated and has a Rf value within 0.3-0.5.
For TLC profiling, 4 TLC plates were prepared for the testing of each solvent. As shown in Figure 1, the green food dye was placed at the bottom center, specifically 0.5 cm away from the bottom of the plate, with the use of a capillary tube. Each one of the silica plates were then vertically placed in a small beaker with its inside surrounded by a filter paper saturated with the solvent to be tested and a small amount of the same solvent at the bottom. The TLC plate was then taken out when the rising solvent was about to reach the top of plate. The ammonia: 1-butanol solvent was tested 7 times due to some personal

TLC profiling
Ammonia in butanol was the appropriate solvent to use for the column chromatography of food dye. After testing for the appropriate solvent, the set- up for column chromatography was done (Figure 2.).
With the use of a clamp, the column was clamped onto an iron stand. A small cotton ball was then pushed in the column until it reached the bottom by using a stirring rod. A small amount of sand was added after the layer of cotton. After that, a layer of silica filled almost 1/3 of the column. Finally, another small amount of sand was added just above the silica. The column was given a little tap with an aspirator to make the silica more compact. Figure 2. Column chromatography set-up
After setting up the column, 2 10-ml of the chosen solvent was obtained and was placed in two separate test tubes. Using a dropper, ~0.5 mL of the food dye was put into the column by dropping it at the side of the column in a circular motion. The chosen solvent was then added just after the green food