Monday, October 18, 2010

CHROMATOGRAPHY, not photography.

Chromatography

  • It is a physical method of separation.
    • the components separated are distributed between 2 phases
    • "mobile phase" and a stationary phase
      • It involves a mixture dissolving in a "mobile phase" though a stationary phase.
  • It is a method of separating and analyzing mixtures of chemicals.
  • The separation process, especially of closely related compounds, by allowing a solution or mixture to seep through an absorbent (such as clay, gel, or paper).
    • so each compound becomes absorbed into a separate, often colored, layer.
  • Different components travel at different rates.
Sheet Chromatography

Paper Chromatography (PC):
  • Is a technique that involves placing a small dot or line of sample solution onto a strip of chromatography paper.
    • The paper is placed in a jar containing a shallow layer of solvent and sealed. As the solvent rises through the paper, it meets the sample mixture which starts to travel up the paper with the solvent.
  • The stationary phase is very uniform absorbent paper.
  • The mobile phase is a suitable liquid solvent of mixture of solvents.
  • It is inexpensive and provides graphic, clear results.
  • Is a rapid and reproducible procedure - as long as all conditions are controlled and maintained.
  • Accurate for the separation and identification of many important organic and inorganic compounds.

Thin Layer Chromatography (TLC):
  • It involves a stationary phase of a thin layer of adsorbent like silica gelalumina, or cellulose.
  • Advantage of faster runs, better separations, and the choice between different adsorbents
  • Is a procedure of chemistry that can identify over 700 types of biochemicals, including significant medical drugs of legal importance.
  • Reliable, rapid and easy procedure.
  • Relatively inexpensive.
  • Able to detect upward of 700 different types of drugs and medications.

By: Hikari Hoshika

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