Urinary iodine assays and ionophore based potentiometric iodide sensors

Urinary Iodine has been widely regarded as a biochemical marker for control of iodine deficiency disorders. Based on the Sandell-Kolthoff reaction, most colorimetric assay methods for urinary iodine (UI) determination that have been developed require pretreatment of urine sample. The non-Sandell-Kolthoff methods for UI assay provide alternative approaches for UI assay requiring only simple pretreatment or even without pretreatment. The selective ionophore-based iodide electrodes are highly applicable to the UI assay for large population due to their high selectivity and sensitivity to iodide, amenability to automation and ease of miniaturization. In this report, different assay methods are reviewed, including pretreatment procedures for Sandell-Kolthoff UI analysis. Finally, a summary of the state-of-the-art of the iodide ionophore-based ISEs that are suitable for UI assays are addressed.