CHM 101/102 Laboratory Manual Chromatography I: Paper General Chemistry 101/102 Laboratory Manual University of North Carolina at Wilmington

CHM 101/102 Laboratory Manual Chromatography I: Paper Purpose Purpose  Use the technique of paper chromatography to separate a homogeneous mixture into its individual components. Safety Considerations Safety Considerations  Butanol and ammonia (both liquid and vapor) are toxic and are strong skin and eye irritants. Keep the ammonia in the hood and cover all butanol and ammonia solutions.  Dispose of butanol in the waste container in the hood.

CHM 101/102 Laboratory Manual Procedure Procedure  Place 25 mL of solvent in a 600 mL beaker. Cover the beaker and set it aside. 25 mL 1 cm 2 mm  Obtain a piece of chromatography paper and draw a line 1 cm from the bottom with a pencil.  Place a small spot of each indicator on the line. Chromatography I: Paper

CHM 101/102 Laboratory Manual Procedure Procedure  Spot and label each of the four indicators and one of the unknowns. The spots should be about 2 cm apart. 2 cm  When the spots have dried, re-spot each one. Chromatography I: Paper

CHM 101/102 Laboratory Manual Procedure Procedure  When the spots have dried, form the paper into a cylinder with the spots facing out. Staple the edges together being careful to keep them straight and not allowing them to touch.  Place the cylinder into the 600 mL beaker and replace the cover. Be sure the cylinder is not touching the sides of the beaker. Chromatography I: Paper

CHM 101/102 Laboratory Manual Procedure Procedure  Let the chromatogram develop until the solvent is 2 cm from the top of the paper.  Remove the chromatogram from the beaker and immediately mark the solvent front with a pencil.  Allow the chromatogram to dry before going to the next step. Chromatography I: Paper

CHM 101/102 Laboratory Manual Procedure Procedure  Take the chromatogram to the hood and lightly mist it with water. Place it in the ammonia chamber.  Remove the cylinder from the ammonia chamber and unroll it. Immediately circle the colored regions with a pencil. Chromatography I: Paper

CHM 101/102 Laboratory Manual Procedure Procedure Chromatography I: Paper  Determine the R F values for each colored spot in the knowns and the unknown. a b c d R F(a) = a d  Use your computed R F values to identify the components of your unknown.