EDTA

from WordNet (r) 3.0 (2006)

EDTA
    n 1: a complex molecule used medically to chelate metal ions in
         cases of lead or heavy metal poisoning [syn:
         {ethylenediaminetetraacetic acid}, {EDTA}]

from The Collaborative International Dictionary of English v.0.48

chelating agent \che"lat*ing a`gent\, n. (Chem.)
   a compound which forms a chelate with a metal ion.

   Note: Commonly used chelating agents in laboratory use are
         {EDTA} and {sodium citrate}. Citrate is used as an
         additive to blood collected in blood banks, to chelate
         the calcium ions and retard clotting.
         [PJC]