Thin Layer Chromatography - Analysis

Analysis

As the chemicals being separated may be colorless, several methods exist to visualize the spots:

  • Often a small amount of a fluorescent compound, usually manganese-activated zinc silicate, is added to the adsorbent that allows the visualization of spots under a blacklight (UV254). The adsorbent layer will thus fluoresce light green by itself, but spots of analyte quench this fluorescence.
  • Iodine vapors are a general unspecific color reagent
  • Specific color reagents exist into which the TLC plate is dipped or which are sprayed onto the plate
    • Potassium permanganate - oxidation
    • Iodine
    • Bromine
  • In the case of lipids, the chromatogram may be transferred to a PVDF membrane and then subjected to further analysis, for example mass spectrometry, a technique known as Far-Eastern blotting.

Once visible, the Rf value, or retardation factor, of each spot can be determined by dividing the distance the product traveled by the distance the solvent front traveled using the initial spotting site as reference. These values depend on the solvent used and the type of TLC plate and are not physical constants.

Read more about this topic:  Thin Layer Chromatography

Famous quotes containing the word analysis:

    “Whatever else American thinkers do, they psychologize, often brilliantly. The trouble is that psychology only takes us so far. The new interest in families has its merits, but it will have done us all a disservice if it turns us away from public issues to private matters. A vision of things that has no room for the inner life is bankrupt, but a psychology without social analysis or politics is both powerless and very lonely.”
    —Joseph Featherstone (20th century)

    “Ask anyone committed to Marxist analysis how many angels on the head of a pin, and you will be asked in return to never mind the angels, tell me who controls the production of pins.”
    —Joan Didion (b. 1934)

    “A commodity appears at first sight an extremely obvious, trivial thing. But its analysis brings out that it is a very strange thing, abounding in metaphysical subtleties and theological niceties.”
    —Karl Marx (1818–1883)