What is an RF solution?

What is the Rf value for plant pigments using a petroleum ether/acetone solvent in paper chromatography?

• I am doing a science fair project using four plant leaves and a petroleum ether/acetone solvent solution. I need to know what the ratio should be (I've seem some 4:1, is that the best mixture?) and I also need to know the general rf values for plant pigments (chlorophyll a and b, Carotene Xanthophyll, etc), so when i record the rf values i can compare them to the general numbers to find out which pigments are in the plants. as detailed as possible please

• Answer:

  At 4:1 you are very close to the immiscibility index for acetone, petroleum ether mixtures. I would cut back on the acetone a bit, or experiment to determine when the mix turns cloudy as you slowly add acetone to the pet ether. Rf values can't be predicted here. Depends on the plant components. Using the plant parts you have, look in chem abstracts or a phytochemistry book under the constituent name/chromatography for a general view. It's best to run a standard sample of the expected chloropyll, xanthophyll, etc alongside as a check.