A method of automatic determination of salt iodine by iodine element detector / 中华地方病学杂志

ABSTRACT

Objective:To establish a method for automatic determination of iodine level in salt by arsenic-cerium catalytic spectrophotometry using an iodine element detector (hereinafter referred to as this method), and to provide reference for in-depth study of salt iodine detection technology.Methods:This method was used to determine the iodine level in salt, and the linear range, detection limit, precision, and accuracy (determination of salt iodine standard substance GBW10006y and GBW10007y, and addition recovery experiment) of this method were determined. The iodine level of 35 salt samples was determined by this method and redox titration method recommended by the national standard, and the results were compared.Results:This method had a good linear relationship within the range of 50 - 600 μg/L standard curve, the absolute value of the correlation coefficients was > 0.999 0, and the detection limit was 5.0 mg/kg. The relative standard deviation of iodine concentration in salt samples with low, medium and high iodine concentrations were all < 6.0%. The determination results of salt iodine standard substance GBW10006y and GBW10007y were within the given value ranges; three iodine concentrations (6.0, 10.0 and 30.0 mg/kg) were added to the salt samples, with an average recovery rate of 96.7% to 105.0%, and a total average recovery rate of 100.9%. The method comparison experiment showed that there was no statistically significant difference between the salt iodine determination results of this method and the redox titration method ( t = - 1.54, P = 0.132). Conclusion:This method has the advantages of high accuracy, good precision and wide linear range in determining salt iodine, and is suitable for the detection of large quantities of samples in salt iodine monitoring.