The combination of ion exchange and ring oven techniques has been used for the separation and detection of trace amounts of a single ion species in mixtures.The microcolumn(1×15-20 mm) was filled with pulverized ion exchange resin powders(Zerolite 225 or Zerolite FF,<200 meshes).A drop of the test solution which contained 10 pg of each of the ions to be separated was introduced onto the top of the column.A suitable eluant(40 μl) which can completely elute one kind of the ions was then led to flow through the column,the outlet of which was contacted with a piece of filter paper placed on the Weisz's oven.Owing to the capillary action,the eluates spread evenly on the paper(flow rate,25-30μl-min.).The microcolumn was then removed and washing continued in order to concentrate all of the eluted ions into the ring.The completeness of the separation was tested with spot tests.