Abstract A rapid, single vessel method for the preparation of clinical grade chelate conjugated monoclonal antibodies has been developed. By use of an Amicon concentrator with reservoir, each of the steps necessary for the preparation of the conjugated drug may be performed in a single vessel. Advantages include reduced risk of metal, pyrogen and bacterial contamination; buffer exchanges are achieved rapidly and efficiently using a continuous dilution method. The radiolabeling efficiency, the radiochemical purity, the total immunoreactivity and the affinity of the final product have been evaluated in the production of CHXA-DTPA-chelate conjugated HuM195. The characteristics compare favorably to those achieved using our conventional synthetic methods.