Determination of Chemically Combined Iodine in Sea Water by Amperometric and Catalytic Methods

., ~ Iodine, in the form of iodides and iodates, exists in sea water in very small concentrations. In previous studies iodine has been concentrated from large samples by precipitation, extraction, or distillation. Using am­ perometric or catalytic methods the iodine may be determined directly on relatively small samples in much less time and with elimination of loss of iodine inherent in other methods. For extensive oceanographic studies the two methods may complement one another. The amperometric method permits ready determination of iodine in the form of iodate and iodide. The catalytic method permits deter­ mination of total iodine more rapidly and accurately than the amperometric method. The difference between the total iodine and the iodate-iodine gives the iodide-iodine. Some data are given for the distribution of iodine in the Northeast Pacific.