Today we will be performing thin layer chromatography. This technique allows us to separate the different components of a mixture. For this experiment we will use a TLC plate, a sample and a solvent. The TLC plate has two sides. Be sure to use the rough side which is coated in silica for the experiment. Using a pencil and ruler draw a line one centimeter from the bottom of the plate, then another line five centimeters above the first line. These lines indicate your start and finish. Draw the lines lightly to avoid scratching the silica off of the plate. Next make a small tick mark in the center of the start line. You will need a tick mark for each sample. Using a micro capillary tube load the sample onto the TLC plate. To load the sample into the micro capillary tube, simply touch it to the surface of the sample. You will see the sample travel up the inside of the tube due to capillary action. Press the tip of the tube briefly to the TLC plate on the tick mark at the start line. Repeat this process until you have a concentrated point of sample. Keep the sample spot as small as possible in order to maximize your resolution. Multiple brief touches with the micro capillary tube are best. To prepare the TLC chamber add five milliliters of solvent. We usually use a seven to three mixture of hexane and acetone. Cap the chamber for several minutes and allow the gases to reach equilibrium. Use four steps to place the TLC plate into the developing chamber. Cap the chamber immediately. The solvent will move rapidly up the plate. If you cannot see the solvent line, try shading the chamber with one hand. Once the solvent line reaches the top line, remove the plate and set it on the bench top to dry. Note, if your sample is not colored, you will have to use a UV lamp to observe the spots.