Recovery of iodine from L-sodium thyroxinate by different ashing methods

The recoveries of iodine in L-Na-thyroxinate were determined by an ashing method at 200-550°C, using three kinds of crucibles. Also the effect of the aqueous extract of “Kombu” Laminaria japonica and the artificial “Kombu” extracts on the recovery of iodine were estimated. The highest value of recovery of iodine was obtained by ashing used in a platinum crucible with alkali at 400°C. Except ashing at 400°C, increasing of ashing time showed a decrease of recoveries. When “Kombu” extract was added to the sample, the recovery of iodine increased remarkably. It will the effect of the mixture of Ca-alginate, mannite and several inorganic element cortained in the aqueous “Kombu” extract.