Determination of iodine in seaweed and table salt by an indirect atomic-absorption method.
Decomposition methods based on fusion with alkali are discussed, with respect to the determination of iodine in biological material. It is shown that sodium hydroxide can be used for the decomposition of seaweed without loss of iodine. In spite of the oxidizing conditions, the iodine will be present as iodide in the final ash. The iodide can be determined by an indirect atomic-absorption method, based on the reaction between iodide and mercury(II), with determination of mercury by cold vapour atomic-absorption spectrometry. The basis of the method is discussed, and it is shown that the use of tin(II) as reductant is essential. The effect of the oxidation state of the iodine on the sensitivity of the method is pointed out. High concentrations of chloride interfere, but it is still possible to determine iodide in iodinated table salt.
Wifladt
A M
AM
Department of Chemistry, University of Oslo, N-0315 Oslo 3, Norway.
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