This is the point where you start to have instrument salesman do some work for you.
First, the instrument companies often have publications on related work. He may
be able to point you to the right internet sight or give you a copy. They usually
also have applications people who can help you out.
If an instrument salesman thinks you will buy and instrument, he will be happy to
have someone at the plant do a feasibility study for you. Don't get me wrong, you
will still have plenty of work to do, but he may be able to get you on the right track.
And you can have all of the different instrument salesman(say IR, NIR, and/or raman)
do the same thing for you.
Good luck.