Radioisotopic carnitine assay using Dowex 50 cation exchanger resin

At termination of the known radioisotopic carnitine assay the incubating mixture was applied to a column of Dowex 50 W x 8 (H+) resin. The [1-14C]acetyl-L-carnitine formed during the incubation bound to the resin, while the excess of [1-14C]acetyl-CoA was washed out with water. Then the radioactivity from the resin was eluted with NH4OH and water into counting vials. The assay is handy, takes much less (one-eights) resin than the known radioisotopic methods and the blank value is insensitive to sample volume.