Workshop Livneh: "Dyes, dyeing and more"

1. Small-scale column chromatography of food dyes using baby food  (Video clip)

Materials
A small beaker (50 mL), glass rod, 0.1% salt solution (eluent), 12 screw capped small vials or Eppendorf small tubes for fraction collection, a small piece of cotton
Pasteur pipette (plastic), two 2 mL syringes,  silicon rubber tube 3 cm, baby food-cornflour (solid phase), a mixture of red and blue food dyes (or other mixture)

Experimental
1. Remove one plunger from on of the syringes, and add a small piece of cotton to narrow part of the syringe bottom.
2. Add to the beaker few spoons of cornflour following by 20-25 mL of 0.1% salt solution. Mix with the stirring rod.
3. Add to the syringe ca. 1.5 mL of the slurry prepared in paragraph 2.  Connect a second syringe to the first one with the silicon rubber tube and slowly push its plunger.
4. Continue the pumping with occasional depletion of the second syringe, until the solid phase in the column syringe is tight and with minimum eluent.
5. Add  one drop of  the dyes’ mixture to the top of the solid phase and draw it a bit inward with the help of the second syringe.
6. Add some eluent solution to the top of the solid phase and start the seperation of the dyes.  During the run use the second syringe as a pump and add more eluent as needed.
7. From time to time disconnect the rubber tube from the syringe and pour the collected liquid into the vials