Determining Caffeine Content in liquids

[lkjhgfdsa]

(I have previously posted a topic similar to this, but did not get my desired answer..)
My science experiment: What is the most effective way to decaffeinate tea at home, requires either measuring caffeine in different liquids, or determining which liquids have more or less caffeine compared to other liquids. However, I cannot find an accurate and simple way to do this without equipment that I don't have access to. I have asked my teacher if I could test my experiment by seeing which tea shows the strongest effects of caffeine when it is consumed. How can I do this experiment?

* I have found previously done science experiments similar to mine such as: http://projects.icbse.com/chemistry-313
For this experiment, the person used lead acetate and chloroform to extract the caffeine from the tea... I'm not sure if this actually works though.

PLEASE help ASAP as I only have a few weeks to complete the project (I had planned to use caffeine testing strips to complete my experiment, but found out that they are not on sale anymore.)

[norman40]

Hi lkjhgfdsa,

I reviewed your previously posted topic at this link:

https://www.sciencebuddies.org/science- ... hp?t=13657

In one of the replies LeungWilley suggested that you ask volunteers to drink tea and decaffeinated tea, then measure the effect on heart rates.

To do this kind of experiment, you'd need to work out a detailed procedure for testing the heart rates of your volunteers before and after drinking each type of tea you want to test. The idea here is to find out how much heart rates change after drinking teas with different amounts of caffeine in them. Heart rates can vary a lot due to factors other than the amount of caffeine in tea. So, you want to include several volunteers and you'll want to plan repeated trials.

You haven't mentioned how you would decaffeinate tea at home. If you choose to ask volunteers to drink your decaffeinated tea, you must be sure that your tea is safe for people to consume. I suggest that you have your teacher review you decaffeination methods before you ask anyone to drink the teas.

I took a look at the link you provided that describes a method for precipitating caffeine from tea extract. This appears to be a method for measuring the amount of caffeine by collecting and weighing the precipitate. The reported results do indicate differences in caffeine contents for three types of tea. So, this might be a workable way to determine caffeine content. If you choose to pursue this test method, please review with your teacher the precautions needed for working with chloroform and lead acetate.

I hope this helps and good luck! Please ask again if you have more questions.

A. Norman

[lkjhgfdsa]

Thank you.