Lab Report 6
Objective:
The objective of the lab is to separate the caffeine samples we are using, using thin layer chromatography. The solvent we are using for the separation is 3:1 mixture of Chloroform and Acetone.
Principle:
Thin layer chromatography (TLC) is an important technique that is useful for separating organic compounds. TLC is often used to monitor the progress of organic reactions and to check the purity of products. Separations in Thin layer chromatography involve distributing a mixture of two or more substances between a stationary phase and a mobile phase. The sample, is dissolved in a solvent, and is deposited as a spot on the stationary phase. The bottom of the plate is placed on a solvent and the solvent moves up the plate due to capillary action. The different components in the mixture move up the plate at different rates due to differences in the way they part between the mobile and stationary phase. The more the distance the better the separation and like dissolves like.
Procedure:
TLC identification of Caffeine: Take a plate and using a pencil lightly draw a line across the plate about 1 cm from the bottom; about 0.5 cm from the edge, lightly mark 1 cm intervals on the line. The marks will represent where the sample spots will be placed. In the first plate your will spot at position #1 with pure caffeine in chloroform, position #2 will be the chloroform sample of caffeine which was isolated in the previous experiment, and position # 3 will be aspirin. After setting up the plate, take a tall beaker and fill it up with the solvent and a strip of filter paper which is about 5cm wide and long. The solvent being used for the separation will be a 3:1 mixture of chloroform acetone. The beaker is filled with this solvent mixture to a depth of about 0.5-0.7 cm so that the origin of the plate is about the level of the solvent. Next you place the plate with the caffeine samples into the chamber and cover it with a watch glass. Allow the chamber to stand
The objective of the lab is to separate the caffeine samples we are using, using thin layer chromatography. The solvent we are using for the separation is 3:1 mixture of Chloroform and Acetone.
Principle:
Thin layer chromatography (TLC) is an important technique that is useful for separating organic compounds. TLC is often used to monitor the progress of organic reactions and to check the purity of products. Separations in Thin layer chromatography involve distributing a mixture of two or more substances between a stationary phase and a mobile phase. The sample, is dissolved in a solvent, and is deposited as a spot on the stationary phase. The bottom of the plate is placed on a solvent and the solvent moves up the plate due to capillary action. The different components in the mixture move up the plate at different rates due to differences in the way they part between the mobile and stationary phase. The more the distance the better the separation and like dissolves like.
Procedure:
TLC identification of Caffeine: Take a plate and using a pencil lightly draw a line across the plate about 1 cm from the bottom; about 0.5 cm from the edge, lightly mark 1 cm intervals on the line. The marks will represent where the sample spots will be placed. In the first plate your will spot at position #1 with pure caffeine in chloroform, position #2 will be the chloroform sample of caffeine which was isolated in the previous experiment, and position # 3 will be aspirin. After setting up the plate, take a tall beaker and fill it up with the solvent and a strip of filter paper which is about 5cm wide and long. The solvent being used for the separation will be a 3:1 mixture of chloroform acetone. The beaker is filled with this solvent mixture to a depth of about 0.5-0.7 cm so that the origin of the plate is about the level of the solvent. Next you place the plate with the caffeine samples into the chamber and cover it with a watch glass. Allow the chamber to stand