SIMPLE CHROMATOGRAPHY

The chromatography is a technique of separation of substances that is based on the different speeds with that each of them through porous means moves dragged by a dissolvent in movement.

The biologists, doctors and chemicals frequently need to separate the components of a mixture as previous step to their identification.

We are going to use this technique to separate pigments used in a commercial red.

What is needed?

  • A strip of porous paper. The filter paper of a coffee pot can be used or to even trim the end (without red) of a newspaper leaf.
  • Labellers or ball-point pens of different colors.
  • A glass
  • A little ethylic alcohol (encuantra in the pharmacies)
  • What is necessary to do?

    It trims a strip of the porous paper that has about 4 cm in width and that is a little but long that the height of the glass.

    Enrrolla an end in a ball-point pen (you can help you of sticky tape) in such a way that the other end arrives at the bottom of the glass. (to see drawing)

    It draws a spot with a black labeller in the free end of the strip, to about 2 cm of the edge. It tries that she is intense and that does not occupy much. (to see drawing)

    Alcohol throws at heart of the glass, until a height of 1 cm approximately.

    It locates the strip within the glass in such a way that the end is submerged in the alcohol but La Mancha that you have made envelope she is outside him. You can cover the glass to avoid that the alcohol evaporates.

    It observes what it happens: as the alcohol is ascending throughout the strip, it drags with himself the diverse pigments that red La Mancha contains. As all are not dragged with the same speed, after awhile strips of colors are seen.

    The experience repeats using different inks.