Buffer-exchange column for rapid separation of carcinoembryonic antigen from perchloric acid

A Sephadex G-50 medium (Pharmacia) buffer-exchange column has been developed for rapidly changing the medium for carcinoembryonic antigen from perchloric acid to acetate buffer. Analytical recovery of the extracted antigen exceeded 95%. Plasma for analysis can be so prepared and samples ready for analysis within an hour. The technique also results in uniform assay volume, thus eliminating this variable from the assay.