Monoclonal Antibodies for Purification and Quantitation of other Molecules - Antibodies have been used for the purification and quantitation of certain molecules present in trace amounts, such as hormones, cyclic nucleotides, polypeptides, enzymes, antigens, etc. The assay is extremely sensitive and quantities as low as nano or picomolar concentrations can be detected in small volumes (l ml) of body fluids such as plasma, urine or cerebrospinal fluid