Science Buddies: "Ask an Expert"

Hello I am trying to do a science experiment where I measure how cooking spinach relates to the levels of chlorophyll.
I know that I can measure the presence of chlorophyll through paper chromatography
but is it possible to measure the different levels of chlorophyll? and how?
I thought you could measure it by the Rf value but my teacher told me that I couldn't and i would have to find a way to measure colour as more amounts of chlorophyll would be greener.

it possible to measure the DIFFERENT levels of chlorophyll through paper chromatography? and how?

Your teacher is correct: Rf values are a measure of the relative distance a band travels, a proxy for the size of the compound traveling along the paper. Since all chlorophyll molecules are the same size, they will all travel approximately the same distance. However, a sample with more chlorophyll will produce a thicker or more dense green band.
In the case of your particular experiment, I'm not sure paper chromatography is a viable option at all, as cooking will denature the protein itself, changing its Rf. More importantly, if that denaturing is at all heterogeneous, the band you get from the cooked spinach may be more spread out (less dense) than the uncooked. In that case, you could not even compare the darkness of the bands to answer your question. You would have to find a way to ensure you capture all of the chlorophyll and compare the concentrations in an identical volume.
Here is a complicated experiment you may draw inspiration from? https://users.stlcc.edu/mhauser/Col%20Chrom.pdf

pharrast wrote: as cooking will denature the protein itself, changing its Rf.

There seems to be some confusion here. Chlorophyll is not a protein, but a pigment structurally similar to heme. Both chlorophyll and heme are typically bound to specific proteins in the living cell (e.g. chlorophyll to photocomplex proteins in plant cells, and heme to hemoglobin in red blood cells), but they're not proteins themselves. Proteins are not separated by paper chromatography (wouldn't that be convenient...), and the pigments are usually run in solvent conditions where most proteins would be denatured, if not insoluble (organic solvents).