Task 2
Thin Layer Chromatography (TLC)
To calculate the retention factor I had to use the formula showed above, with the distance travelled
by the solvent front being 3.6cm. As the results table shows the unknown solution contains lysine.
The reason that this is evident is because they both travelled the same distance on the TLC sheet.
Glycine travelled the most distance (1.2cm) with lysine and the unknown solution after (1.1cm). My
aim was to identify the components from the unknown solution which is lysine. In the beaker
containing butanol, ethanoic acid,water the results table show that the components in the unknown
solution match the lysine therefore there is enough evidence to conclude that the unknown
solution consists lysine.
Gel Permeation chromatography
Starch
For the 1st, 4th, 5th, 6th, 7th, 8th, 9th and 10th test tubes the results table show that there is no
colour change, this means that no starch is present. However in test tubes 3, 4, and 5 the colour
changes to dark blue and black which indicates that there is starch present.
Starch is what's called a polymer, starch comes in long chains of glucose monomers, that have
been fused .4 Starch is composed of two different molecules, amylose and amylopectin. 1Amylose
is a long straight chain of glucose molecules whereas amylopectin has branches at every 25th
glucose or so. Test tubes 2, 3 and 4 are starch because iodine forms a complex with starch,
resulting in the dark blue or black solution. The amylose, or straight chain portion of starch, forms
helices where iodine molecules assemble, forming a dark blue/black colour.
Glucose
From the results table it is evident that the first 5 and the last 2 test tubes do not contain any
glucose as there is no colour change. In first 5 and the last tests tube doesn’t contain any glucose
because the colour didn’t change. Test tubes 6, 7, and 8 contain glucose as the colour has
changed to brick red and green.
Glucose is a sugar molecule that contains carbon, hydrogen and oxygen atoms. 2 Glucose is a
monomer, one 'unit' of glucose, is small, whilst starch comes in long chains. So glucose is the
building blocks of starch chains.4
Benedict Solution is light blue because it contains copper sulphate. When it is mixed and heated
with glucose, which has electrons available to donate, the copper accept the electrons and
become reduced, which turns it brownish-orange 3. During this process, the blue copper ion is
reduced to a red copper ion. While the copper is being reduced, the glucose gives up an electron
and is oxidized. Because glucose is able to reduce the copper in Benedict Solution
Benedict's solution changes the colour of glucose to a yellowish orange colour. This is because it
causes a chemical reaction in the glucose breaking down the copper bonds in the solution. Starch