Terbium chelate for use as a label in fluorescent immunoassays.

Human serum albumin has been labelled with a terbium complex by means of a reagent prepared from the bis-cyclic anhydride of diethylenetriamine pentaacetic acid and p-aminosalicylic acid. This reagent combines high fluorescent intensity with stability at high dilution (10–9M). The fluorescent conjugate so produced has been used in a simple fluoroimmunoassay, using human serum albumin as a model analyte.