Idon't know off hand where you can find such an antibody.
However Dr. Ken Pass in Albany, New York at the New York State
Department of Health runs the largest newborn screening
laboratory in the United States and although they
routinely use the common cellulose acetate and citric acid
electrophoresis assays they have in the past
experimented with ELISA for hemoglobin S. I'm sure he would
know of a source.