lab 2

• What is the purpose of Thin Layer Chromatography (TLC)?

  Separation of compounds with structural similarities
• What is the stationary phase used in TLC for amino acids?

  Silica gel (silicon dioxide)
• What is the mobile phase in TLC typically composed of?

  Organic solvent or mixture of solvents
• How does the mobility of amino acids in TLC vary?

  Based on their retention by the stationary phase
• What is the distance of the starting line from the base of the TLC plate?

  About 1 cm
• How far apart should the sample spots be on the TLC plate?

  1.5-2 cm apart
• What diameter should the sample spots be when placed on the TLC plate?

  Approximately 5 mm
• What should not be wet by the developing liquid in TLC?

  The area where the sample spot is placed
• When should the TLC plate be removed from the chamber?

  When the mobile phase is 2 cm from the top
• What is used to visualize the amino acids on the TLC plate?

  Ninhydrin solution

  
• What color do amino acids turn when reacted with ninhydrin?

  Violet

  
• What is the formula for calculating the retention factor (Rf)?

  Rf = Distance traveled by compound / Distance traveled by solvent front
• What factors can affect Rf values?

  Solvent systems, stationary support, and temperature
• What materials are needed for the TLC experiment?

  • Amino acids standards
  • TLC plates
  • Capillary tubes
  • Beaker (or chamber)
  • Mobile phase solvent system (propanol: water (7:3))
  • Watch glass
  • Ninhydrin
  • Oven
  • Fume Hood
• What is the concentration of amino acids in the prepared solutions?

  1 mg/ml
• How should the starting line be marked on the TLC plate?

  Lightly with a pencil, parallel to the base
• What should be done after marking the starting line on the TLC plate?

  Mark the sampling and standard points
• What should be done with the mobile phase solvent system in the experiment?

  Place it in a beaker or chamber
• What is the purpose of closing the growth chamber with a lid?

  To allow the mobile phase to flow properly
• At what temperature should the TLC plate be placed in the oven?

  110°C
• What should be done if the spots on the TLC plate are broad?

  Measure from the middle of the spot
• How are the amino acids identified after the experiment?

  By comparing with bibliography