Methodological evaluation of an automatic iodine element detector for measuring water iodine / 中华地方病学杂志

ABSTRACT

Objective:To evaluate the feasibility of using an automatic iodine element detector to detect water iodine.Methods:Water iodine was determined by an automatic iodine element detector. The methodological characteristics of this method was tested, including linear relationship of standard curves, precision tests, standard recovery experiment, and certified reference material GBW09113j, GBW09114j determination experiments. The methodological comparison experiment was conducted using arsenic cerium catalytic spectrophotometry.Results:Using an automatic iodine detector, in the range of 2, 10, 20, 40, 60, 80, 100, and 120 μg/L standard curve, the correlation coefficient ( r) for six parallel measurements ranged from - 0.999 9 to - 0.999 6. Precision analysis showed that the low, medium, and high iodine concentration water samples were measured six times in parallel, with corresponding coefficient of variation ( CV) of 2.2%, 3.0%, and 3.2%, all of which were less than 5%. The standard recovery experiment showed that the recovery rates of low, medium, and high iodine concentration water samples after two rounds of standard were 97.0%, 98.8%, and 99.5%, respectively, with a total average recovery rate of 98.4%. The detection results of the two reference materials were within the range of the given standard given by the national standard values [(8.2 ± 1.2), (61.0 ± 6.0) μg/L]. The iodine content of 30 water samples was determined by the automatic iodine detector and the arsenic cerium catalytic spectrophotometry, and the results showed no statistically significant significance ( t = - 1.62, P = 0.116). Conclusions:Although the concentration range of standard curve does not cover 0 - < 2 μg/L, the determination of water iodine by automatic iodine detector has advantages of high automation, high precision, good accuracy, and the results are in good agreement with the results of arsenic cerium catalytic spectrophotometry. It has good application prospects in water iodine determination.