Objective: To establish a method of ion chromatography for urine iodide determination and evaluate its application in epidemiological studies.
Methods: Urinary iodine was determined using ICS-2500 ion chromatography coupled with IonPac AS7 analytical column (4 mm x 250 mm), silver electrode and direct current amperometry for 467 elderly subjects (above 50 years) with their urinary Tsh and FT4 also determined. The history of thyroid diseases was examined among these subjects.
Results: The peak area of the ion chromatography was linearly correlated with urinary iodine concentration, with the correlation coefficient of 0.9999. The detection limit of iodide was around 3.5 microg/L (S/N=3), with coefficients of variation ranging from 3.16% to 3.45% and mean recovery rate of 95%. The urinary iodine level in the 467 elderly subjects showed a positively skewed distribution with the median level of 224.7 microg/L.
Conclusion: Ion chromatography for urinary iodine determination has excellent selectivity, sensitivity, reliability, accuracy and stability, and may ensure satisfactory effect for application in epidemiological studies.