I recently described a citation format checker for ACS journals. Now I present a web page that allows you to check your actual references, not just the format. This is powered by PubMed (using BioPython) and CrossRef (explained here), currently the only two publicly available sources of journal metadata for Biology and Chemistry journals.
Simply copy your footnotes from your Word document, paste into the form in the ACS citation checker, and click "Check". This will check just the first reference; repeated clicks on "Check" will check each reference one after the other.
Although CrossRef recently (see comments here and here) improved the quality of the metadata it supplies over its public API, where the metadata is also available in PubMed, PubMed typically wins out (e.g. CrossRef is missing the title for several of the papers in my test case).
I have set up this service for ACS publications. If you're interested in setting this up for other journals, perhaps we could collaborate on sharing code, etc. Of course, if you're a publisher and wish to improve the quality of the references submitted, feel free to make me an offer I can't refuse. :-)