Methodological evaluation on determination of urinary iodine by an automatic iodine analyzer

Objective To evaluate a method for determining the iodine content in urine by an automatic iodine analyzer. Methods The iodine content in urine was determined by an automatic iodine analyzer. Methodological experiments were carried out on the method (including test standard curve linearity and detection limit, precision test, spike recovery test, standard substance determination experiment, method comparison test). The urine samples from the method comparison were obtained from 27 pregnant women collected from Nantantou Village, Baoshan Street, Licheng District, Jinan City, Shandong Province. and the results of the same samples were compared with the results determined by arsenic-cerium catalytic spectrophotometry (GB method). Results The absolute value of correlation coefficient of the mass concentration range (0 - 300 μg/L) standard curve was > 0.999 0, the detection limit was 2.9 μg/L (the sample volume was 0.25 ml). Precision: the coefficient of variations of the three iodine concentrations in the range of low, medium and high were 3.8%, 3.1%, 2.3% (n = 18), respectively. Accuracy: the average recoveries were 98.8%, 99.5%, 101.2% of low, medium and high urine samples in the range of curves (n = 6), and the total average recovery was 99.8%. The measurement results of two urinary iodine standard substance were in the standard value range. Methods comparison experiment: there was no significant difference between the results of 27 urine samples measured by two methods (t = 0.40, P > 0.05). Conclusions The method of automatic iodine analyzer in detection of urinary iodine has higher precision and accuracy, less reagent dosage, and simple operation. It is suitable for detection of large quantities of urinary iodine samples. Key words: Urine; Iodine; Automatic iodine analyzer