After which we dissolve the coloured coating of the M&M chocolates by filling the test tube with acetic acid and placing them in the boiling water of beaker, just like what we did for the wools. Next, we transfer the coloured solutions to a new test tube.
We then heated the coloured solutions in conical flasks on a hot plate to concentrate the solutions, so that we can see the colours more obviously.
Lastly, we spotted some standard colourants and our coloured solutions onto the silica gel plate to do the Thin Layer Chromatography analysis. Afterwards, we calculated the Rf values of the colourants from the M&M chocolates and the standard colourants.
I learnt how to do Thin Layer Chromatography and the importance of knowing the right amount of artificial food colouring used. Today's session has deepened my knowledge on food sciences and analysis and I am more interested in knowing other methods of food analysis.