Add 3cm^3 of solvent to each of the 3 boiling tubes and put a bung in the top before storing in the rack.
Label the tubes 'S' (Spinach), 'D' (Dark Baby Red Leaf) and 'R' Red Chard using the marker pen.
Label the strips of paper 'S' (Spinach), 'D' (Dark Baby Red Leaf) and 'R' Red Chard using a pencil.
Using a ruler and the pencil, draw a line 2cm from the bottom of each strip. This is the origin line.
Cut a disk of Spinach using the borer, avoiding the veins as much as possible.
Put the disk on the centre of the origin line on the paper marked 'S'. Place the paper onto the white tile and crush the disk using the glass rod to leave a stain.
Attach the paper to the paper clip of the bung of the 'S' tube and replace the bung in that tube.
Wait for the solvent to travel up the paper until it almost reaches the top.
Remove the paper and immediately draw a pencil line to mark where the solvent reached. Remember to replace the bung in the tube. This paper is your chromatogram.
Wait for the paper to dry and then draw a ring in pencil around each coloured spot to be seen.
Repeat steps 4-9 for Dark Baby Red Leaf and Red Chard.
Calculate the Rf value for each pigment spot on the chromatogram using the formula below.
Compare the Rf values with an appropriate reference to estimate and identity of the pigments.
Compare results with other groups.

Rf value = distance between spot and origin
distance between solvent line and origin

	Criado por Eleanor H mais de 7 anos atrás

Methodology and applications of an example of Required Practical 7 for AQA A-Level Biology. Use of chromatography to investigate the pigments isolated from leaves of different plants eg leaves from shade-tolerant and shade- intolerant plants or leaves of different colours