wow, you're going to measure all of the different biochemicals in leaves with a single instrument? Good luck...
HPLC might be the machine you are looking for, probably with at least a mass spec detector. This will separate the components of the inevitable mixture that you will be getting from the leaf into some of its myriad of components, and the MS detector will tell you the molecular weight of each component, assuming that they are pure components. If you have samples of the pure components to test against, you can also calibrate your spectra to give you the concentration of each component in your mixture. NMR would probably be the best machine for identifying each pure component once you have isolated it, but you're going to be overwhelmed with peaks if you try to run an NMR on a mixture.