It can be done, there is a member here who actually has done this. But its project that you could get done in a weekend. Maybe when he (benzyme) comes back you can ask him.
But its no simple investment, be prepared to invest at least that of a used car in ordering new parts, tools, etc. Troubleshooting the machine itself is a whole another investment as well, the time it takes to get to know the machine, there is always some problem that needs to be addressed even in brand new machines, let alone old ones.
HPLC also needs dedicated gas cylinders, nitrogen and helium, for running the pumps and sparging the solvent for the samples..
So not cheaply, not easily, I expect if your a working person it would take up nearly all of your hobby time to get it up and running in a reasonable amount of time (6 months maybe).
Definitely talk to benzyme if you get the chance, hehe he knows exactly how to answer your questions.
Expect nothing, Receive everything.
"Experiment and extrapolation is the only means the organic chemists (humans) currrently have - in contrast to "God" (and possibly R. B. Woodward). "
He alone sees truly who sees the Absolute the same in every creature...seeing the same Absolute everywhere, he does not harm himself or others. - The Bhagavad Gita
"The most beautiful thing we can experience, is the mysterious. The source of all true art and science."