Hi I'd like to broach, in an open forum, the question of how to identify molecules in a solution.

Ideally, chemistry used to be a hit and miss process. There are hundreds of years of techniques for extracting, purifying and separating the components of a solution.

The more recent (30 years) science of exactly identifying components and strength of solutions is a more recent phenomenon. Also the miniturization of computer components, and the mass market production of electrical instruments in the last 15 years has lead to a simplification (cheaper) of the device involved in identifying molecules.

My simple question (with a complex answer) whats the cheapest solution to be able to identify (programmatically or looking up tables) which molecules are what? Also, same question but proportions of each molecule?

I've posted before a great link to MIT chemistry, which has detailed videos on HPLC and also TLC. Have a look.

Indeed which is my inspiration.. but my question is related to cost..

TLC is the only way that's affordable besides simple reagent tests for starch or something. Even if you could buy a used HPLC or Mass spectrometer the running and operational costs would get cumbersome. You need gas lines and tanks you need lots of solvents columns all things that add up to $$$. TLC is the cheapest and easiest way to how to ID compounds in mixtures or to check for purity. However it does have short comings in that seperation power is not as good and ID can be hard if not impossible without references or other techniques available.

The MIT vids are great for TLC. I learned a tremendous amount of practical stuff.

Agreed! It made me envious of the knowledge contained in them! I used to think (when i was learning it in chemistry) "why the hell do you need TLC" then i saw the film about column chromatography! The missing link of course is sure you've just extracted a pure solution; how the eff do you know what it is? Actually i'm enjoying getting back into chemistry.

Okay this has been established... HPLC is expensive (i'll prolly buy one when i retire in 30 years).. Although, I think it may seriously be worth it. Imagine isolating the potencies and components of every known psychoactive cactus (or even better, the fast growers which are unknown to cause psychoactives). Imagine finding a peyote replacement! a fast potent grower.

<--- avatar is hplc (varian vista 2150 pump, Applied Biosystems 785A UV-Vis detector).

the minimum components required to run HPLC is a pump, tubing/fittings, sample injection valve, column, detector, and a recorder. this can all be acquired for 1G or less, if you look around.

it also helps to have a degasser.

hplc isn't plug and play though. column selection is very important, as is elimination of system issues such as dead volume.
max abs. values for various compounds are listed in the Merck index

Thats the schiznitz. I knew there was someone out there with a setup.. So what about operating costs?

for just absorbance spectroscopy, operating costs are modest, like running a tv.
it's when operating a mass spec that it gets rather costly. they use loads of energy and emit alot of heat.