Introduction to chromatography

• What is the name of the separation method discussed in the study material?

  Chromatography
• What is chromatography used for?

  To separate mixtures into their components for analysis, identification, purification, or quantification
• What are the main objectives of chromatography?

  • Analyse a mixture and its components
  • Identify components based on known substances
  • Purify components for further study
  • Quantify the amount of components present
• What causes separation in chromatography?

  Different compounds have varying 'stickiness' to the stationary and mobile phases
• What are the two phases in chromatography?

  • Stationary phase: solid material that absorbs the mixture (e.g., paper)
  • Mobile phase: liquid that transports the substance through the stationary phase
• In which industries might chromatography be used?

  Pharmaceuticals, hospitals, law enforcement, environmental agencies, and manufacturing plants
• What are the different types of chromatography mentioned?

  • Paper chromatography
  • Thin-layer chromatography (TLC)
  • High-performance liquid chromatography (HPLC)
  • Gas chromatography
  • Column chromatography
• How does paper chromatography differ from thin-layer chromatography (TLC)?

  Paper chromatography uses paper as the stationary phase, while TLC uses a glass plate with silica gel
• What happens to different ingredients in a mixture during chromatography?

  They are carried along at different rates and end up in different places
• What is the Rf value in chromatography?

  • Rf value is the ratio of the distance traveled by the solute to the distance traveled by the solvent front
  • Rf values range from 0 to 1
• Why is the solvent front line marked in chromatography?

  To indicate how far the solvent has traveled once it dries
• Why is the origin line drawn in pencil in chromatography?

  Pencil does not dissolve in the solvent and will not interfere with the results
• How is the Rf value calculated?

  By dividing the distance traveled by the solute by the distance traveled by the solvent front
• What are the steps to perform chromatography?

  1. Draw a pencil line on the paper or TLC plate.
  2. Add drops of each sample to the line.
  3. Allow samples to dry and add another drop.
  4. Place the paper in a solvent container.
  5. Cover and wait for the solvent to rise.
  6. Remove and dry the chromatograph.
  7. Calculate the Rf value.
• What is the role of water in chromatography with non-permanent markers?

  Water carries the pigment onto the chromatography paper
• What does it mean if an Rf value is close to 0?

  The solute remains fixed at its origin
• What does it mean if an Rf value is close to 1?

  The solute is very soluble and moves as far as the solvent
• What are the good and bad points about the chromatography experiment?

  Good points:

  • Simple and effective for separation
  • Can analyze multiple samples at once

  
  

  Bad points:

  • Time-consuming
  • Requires careful handling to avoid contamination
• How many ink samples were separated in the thin-layer chromatography investigation?

  8 samples
• Which samples were identified as pure substances?

  A, B, and D are pure substances
• How were the most impure samples identified in the investigation?

  Samples i, ii, and iii were identified as the most impure due to containing four components
• What is the purpose of chromatography in scientific procedures?

  • To separate mixtures into their components
  • To analyze, identify, purify, and quantify substances
• What will be covered in the next lesson regarding chromatography?

  • Chromatography of amino acids
  • Types of amino acids (non-polar, polar, charged)
  • Definitions of polar and non-polar