Abstract:

Objective To obtain a simple，efficient，accurate，sensitive and low-cost method for the detection of iodine content in human urine samples，and to prove that this method can replace the traditional arsenic-cerium catalytic spectrophotometry for the detection of iodine in urine samples. Methods The fully automatic online digestion iodine analyzer was used to directly quantify urine samples after automatic online digestion. At the same time，the traditional arsenic-cerium catalytic spectrophotometry was used to determine the curve of urine iodine standard solution and urine iodine composition analysis reference material，then analyze the differences between the two methods in terms of linear correlation coefficient，method detection limit，accuracy and precision of the standard curve. A total of 400 urine samples from special populations were tested by two methods，and the test data were analyzed. Results Both of the two methods had a good linear relationship in the range of iodine content of 0-300 μg/L and 300-1200 μg/L，and the correlation coefficient（r） was greater than 0.999 0，and the detection limit of the iodine analyzer method was 1.92 μg/L，and that of the traditional spectrophotometric method was 2.90 μg/L. The measured values of the reference materials for the analysis of urine iodine composition at 4 concentrations by the two methods were within the specified range. The relative standard deviation（RSD） of iodine analyzer method was 1.369%-2.042%，and that of traditional spectrophotometry was 2.738%-3.822%. The recovery experiment showed the recoveries of iodine analyzer were 93.53%-104.03%，and 91.37%-104.33% for the traditional spectrophotometry. There was no statistically significant difference in the detection results of 400 urine samples from different groups of special populations（all P>0.05）. Conclusion The automatic online iodine digestion analyzer method is consistent with the traditional spectrophotometry method in terms of accuracy and reliability of detection results，and is more reliable in terms of stability. It has higher reproducibility and more precise control of experimental conditions. At the same time，it can save manpower and reagent costs，reduce pollution，and is especially suitable for the rapid detection of large samples of grassroots units.

Key words: Urine iodine, Automatic online digestion of iodine analyzer, Arsenic-cerium catalyzed spectrophotometry