Abstract: Objective To assess the application significance of the new iodide ion-selective electrode for the determination of urine iodine. Methods Performance parameters and selectivity coefficients of the new iodide ion-selective electrode were measured according to the national mechanical industry standard JB/T9362-1999 Technical Specifications for the Ion-Selective Electrode. National standard reference materials(GBW09108-GBW09110) were performed for the new iodide ion-selective electrode to evaluate the accuracy. Urine iodine ion concentrations of 126 urine samples were determined by the new method, and the results were compared with the national health care industry standard method-arsenic cerium catalytic spectrophotometric determination(WS/T107-2006). Results The detection range of the new iodide ion-selective electrode was 50-690 μg/L with a slope ≥ 55 mV, the time to response < 2 min, the applicable pH range 2-10, the internal resistance < 500 kΩ, repeatability error < 2 mV, stability <±8 mV/24 h and the range of applicable temperature 5-60 ℃. The selectivity coefficients of the new iodide ion-selective electrode to Cl^-, S^2- and etc. reached 10^-7 grade. The interference of co-existing organic materials was eliminated. The determination results of the national standard reference materials were within the standard value range.There was no statistical significance between the results of urine iodine ion concentrations of 126 urine samples by the new iodide ion-selective electrode and standard methods(t=0.527,P=0.604). There was a good correlation between the 2 methods, and the linear regression equation was Y=0.972 9X＋4.484 5(r=0.978 7). Conclusions The new iodide ion-selective electrode can be used for the determination of urine iodine ion.

Key words: Iodine, Urine, Ion-selective electrode, Ion selectivity coefficient