b. Add the net counts within the 243 Am channels to obtain total net counts. ec. Divide total 241Am counts by total 243Am counts and multiply this ratio by the total dpm 243m added: 241 counts , dpm 243 Am added = dpm 241 am 243 am counts NOTE 1: If there is a substantial amount of residue after evaporating the eluate from the cation resin column (Step 12) and if the first hydroxide precipitate after the cation resin column is a light tan in color and further hydroxide precipitates don't darken (Step 14), repeat the cation resin column (Step 10). A~-11-4