Analysis of Organic Iodine in Drinking Water

Oral Presentation

Prepared by D. Reckhow
UMass, 18 Marston Hall, CEE Dept, Amherst, MA, 01003, United States

Contact Information:; 413-545-5392


With new and more sensitive instruments we are now able to detect iodinated organic compounds in US drinking waters. While some are naturally occurring plant products, others are used in medicine and industry and enter into raw drinking waters as municipal wastewater contaminants. Still, there is a third category of iodinated compounds, a group that is produced as unwanted byproducts of the oxidation and disinfection of drinking water. These belong to a class of compounds known as disinfection byproducts (DBPs) which include chlorinated, brominated and iodinated organic compounds. Toxicity tests have shown the iodinated DBPs to be much more toxic than the brominated or chlorinated DBPs. As a result, drinking water utilities are especially concerned about their presence in finished water.

In this paper a set of new methods for measuring iodinated organic compounds in drinking water will be presented and compared. The first is a total assay, total organic iodine (TOI) that employs activated carbon adsorption, combustion, trapping and final analysis by ICP/MS. The high sensitivity of ICP/MS for iodide allows detection of TOI at very low levels, whereas conventional methods (i.e., ion chromatography) do not. The second is an LC/MS/MS method (Xevo QTOF) that uses collision energy switching (MSE). In this method we take advantage of the abundant iodine daughter ion with the high resolution of the TOF to get excellent sensitivity along with considerable structural information.