In the classic experiment (Miller & Urley, 1953) the critical part of the "broth" was amino acids and other chemicals normally associated with life. See
http://tidepool.st.usm.edu/crswr/millerurey.html
Today scientists are focused on the role RNA might have played as the first replicating molecule (wow, DNA wasn't first!). Some researchers are reporting how RNA can be formed from molecules on clay. Cool. See
http://www.origins.rpi.edu/clayandtheoriginsoflife.html
Ooops, forgot to mention that the incredients for the "broth" are whatever chemicals might have been present on a very early Earth.
Try the Wiki on the subject at
http://en.wikipedia.org/wiki/Origin_of_life
Specifically from the Wiki article, and I think the answer to your question, "the basic inorganic chemicals from which life was formed are methane (CH4), ammonia (NH3), water (H2O), hydrogen sulfide (H2S), carbon dioxide (CO2), and phosphate (PO43-)."
Best regards,
-Jeff in Michigan