Which describes the basis of an immunoassay? An electron beam excites atoms within the drug, which give off a characteristic
X-ray spectrum.
The drug gets carried through a stationary phase by a mobile phase and the
retention time identifies the drug.
The unknown amount of drug in a sample competes with a known amount of
fluorescently labeled drug for binding to an antibody to that drug.
The drug fragments have specific molecular weights that bind to the antibodies.