chromatography

• What is chromatography used for?


  to separate photosynthetic pigments
• how do you create the pigment solution for chromatography


  tear up leaves and grind with acetone to form a dark green pigment solution
• why do we add acetone to the pigment solution


  acetone dissolves the phospholipid membrane making the membrane more permeable and allowing the leakage of pigments
• what is acetone


  an organic solvent
• in the chromatography practical what happens after acetone has been added to the pigment solution


  using a capillary tube spot the pigment onto chromatography paper
• in the chromatography practical what happens after the pigment has been spotted onto the chromatography paper


  place the chromatography paper into a solvent (such as petroleum or acetone)
• what solvents can be used in the chromatography practical


  acetone or petroleum
• why do we need a solvent in the chromatography practical


  to dissolve and carry the pigment up to the chromatography filter paper
• in the chromatography practical what happens after the solvent has made its way up the filter paper


  remove the chromatography paper and observe the distances of the pigments travelled
• at what point during the chromatography practical do you remove the chromatography paper


  when the solvent has reached the top of the paper
• why do pigments travel different distances


  the more soluble or smaller the substances the further they move
• what is meant by the RF value in chromatography


  this is distance travelled by the pigment / distance travelled by the solvent
• how do you identify the different pigments in chromatography


  by comparing the Rf values to known values