Tlc Lab

This study was conducted with a partner, since some parts of the experiment were able to be done simultaneously. One partner prepared a TLC developing jar by pouring a small layer of 4:1:1 propanol/acetic acid/water into a developing jar. A solvent wick was made by wetting a piece of filter with the solvent, and it was placed in the jar. A silica coated TLC plate was obtained, and a spotting line was carefully drawn approximately 1.5 cm from the bottom of the plate using a pencil. Extra care was taken to not touch the plate with bare skin. Five spots were labeled on the line and each amino acid standard was spotted on the plate using a capillary tube. The standards included leucine, alanine, phenylalanine, and lysine. The final spot was an unknown mixture of three amino acids. After allowing the spots to dry, the plate was placed in the developing jar and allowed to develop. The TLC setup is shown in Figure 2. Once the solvent front reached a considerable distance, the plate was removed from the jar,

The setup for the cation exchange chromatography is shown in Figure 3. This was done by plugging the bottom of a burette with a small amount of glass wool. The wool was lightly packed using a thermometer. Approximately 5 mL of Dowex 50 cation exchange resin was obtained in a small beaker, and the resin was mixed with 5 mL of pH 3 citrate buffer. This mixture was poured into the burette with the stopcock closed. The resin that had stuck to the sides of the burette was washed down by pipetting extra pH 3 citrate buffer along the sides. The column was tapped to ensure that the settled resin formed a level surface. After all of the resin settled, the buffer was drained into a waster beaker until the level of the buffer reached the top surface of the resin. For the remainder of the experiment, the top surface of the resin was not allowed to dry