Aunt Bean is looking for a chemist to measure the levodopa content of her fava beans. I would like to measure the dopamine content of banana skins.

The only reference to a DIY solution to this problem that I can find is in a blog by Ken Allan
http://home.cogeco.ca/~allan/beans.html
He describes how to use the colour of a solution to measure the levodopa of the fava beans that he grows.

Now the last chemistry lesson I took was 42 years ago, so my ideas on the subject probably aren't worth a bean, especially one of Aunt Bean's fava beans, but here goes!

Could you use a levodopa/carbidopa (Sinemet) pill as a reference, separating the two by using their different solubilities in water and ethanol?

Could you do a simplified voltammetric analysis: measure the current through a solution at different voltages?

I'd be grateful to anyone who came up with a "kitchen sink" method.

John