The purpose of this experiment is to identify plant pigments by separation, using thin layer chromatography.

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Thin Layer Chromatography

Aim: The purpose of this experiment is to identify plant pigments by separation, using thin layer chromatography.

Thin Layer Chromatography

Thin Layer Chromatography (TLC) is a chromatographic technique that is used to separate mixtures. It is very commonly used in synthetic chemistry for identifying compounds, determining their purity and following the progress of a reaction. One of the solids that are mostly used in chromatography is silica gel. There are many uses of thin layer chromatography which are:

  • To determine the number of components in a mixture.
  • To determine the identity of two substances.
  • To monitor the progress of a reaction.
  • To determine the effectiveness of a purification.
  • To determine the appropriate conditions for a column chromatographic separation.
  • To monitor column chromatography.

Thin Layer Chromatography is a fast and a simple analytical technique. TLC involves spotting the sample to be analysed near one end of the sheet that is coated with a thin layer of an adsorbent. The sheet can be the TLC slide and this is placed on end in a covered jar containing a shallow layer of solvent. As the solvent rises by capillary action up through the adsorbent and different positioning occurs between the components of the mixture dissolved in the solvent. The more a given component of a mixture is adsorbed onto the stationary phase, the less time it will spend in the mobile phase and the more slowly it will migrate up the TLC slide.

Biomass is a biological material derived from living organisms. In the context of biomass for energy, this is often used to mean plant based material, but biomass can equally apply to both animal and vegetable derived material.  Biomass is the dry mass of a living organism. It is simply the actual mass minus the total amount of water. It is calculated by baking an organism in an oven and evaporating off the water present. Biomass can be burned directly, or converted into a gas or oil, to generate electricity and heat. It can also be converted into bio fuels or liquid fuels for our transportation needs. There are many ways of turning biomass into electricity and heat such as direct combustion, co-firing, gasification, anaerobic digestion and pyrolysis.


Energy and its supply is a concern for the government, and an energy hungry population.  As fossil fuel supplies start to dwindle more emphasis is now being placed on renewable sources of energy, one being biomass fuel.  This is plant material that is grown to produce a fuel to be burnt in a power station.  However, companies need to know which plant would be best to grow, and they have turned to me to investigate some possibilities. I will see which plant has the most pigments, and can absorb the most light energy so if it grows bigger or faster to a better biomass fuel option. 

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  1. Measure 2cm from the bottom of the TLC slide using a ruler
  2. Draw a line across the slide using a pencil horizontally. This is the origin, the line on which you will spot the plant dyes.
  3. Draw two lines vertically across the slide
  4. The TLC slide is ready to use
  5. Use scissors cut up 1g of fresh leaf tissue
  6. Grind the grass with sand and ...

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