Science Buddies: "Ask an Expert"

We are doing an experiement that has to do with the amount of chlorophyll in various plants. We were wondering how we can test the chlorophyll in the leaves using a spectrophotometer. The spectophotometer can only measure liquids.

Thanks for your help

Hi shortnsweet,

Your best bet is to try and extract the chlorophyll from the leaves into a suitable solvent. This will allow you to use the spectrophotometer to measure the amount of chlorohphyll present.

What research have you done so far? I just tried a search for "Chlorohphyll Extraction" on Google and was able to find quite a bit in a very short space of time

Think about your extraction technique and what solvent you might use - and why.

You will also want to consider how you are planning on comparing one plant to another. That is, what does one measurement *mean* when compared to another plant or plants? This is more to do with the experimental design in that you need to be able to quantify your results. Have a think about how will control all of the variables involved, and let us know your thoughts.

Also, what have you been able to discover about using the spectrophotometer? What wavelength(s) are you planning on using, and why?

So, some food for thought! This sounds like an interesting project - so please keep us informed of your progress.

Best wishes,
Geoff.

Hi there,

I would suggest, as Geoff did, that you use google to search for "chlorophyll extraction" and "chlorophyll spectrophotometer". Several very useful articles come up that will give you some ideas for your experiment.

Here are a couple of good papers for you to read - they will give you an idea of some the things you need to consider when designing your experiment. Use these as example for generating ideas only - be sure to design your experiment specifically to test what you are measuring. There are several other good websites to look at also.

http://scidiv.bcc.ctc.edu/rkr/Biology20 ... tra201.pdf
http://www.rsmas.miami.edu/groups/niehs ... 0Expt2.pdf

As Geoff asked - are you planning on comparing plants to one another? which ones? What is the best solvent for extraction? How will you quantitate and compare the amounts of chlorophyll? Will you need to set up a standard curve or calibration curve? What controls do you need? How will you present your results?

I hope this helps. Good luck with your experiment. Let us know if you have any more questions.

Mary