Determination of iodine in serum: verification of inductively coupled plasma mass spectrometry / 中华地方病学杂志

ABSTRACT

Objective:To verify the determination method of iodine in serum by inductively coupled plasma mass spectrometry (ICP-MS) and to evaluate the consistency between ICP-MS and As 3+-Ce 4+ catalytic spectrophotometry in determination of serum iodine. Methods:Serum iodine concentration was determined by ICP-MS, 187Re was used as an internal standard, and ralated parameters were optimized. Eighty-eight serum samples were simultaneously determined by ICP-MS and As 3+-Ce 4+ catalytic spectrophotometry, and the evaluation indexes included determination range of standard curve, detection limit, precision, accuracy. In addition, we also evaluated the consistency of the two methods through inter-group correlation analysis, intra-group correlation coefficient analysis, Passing-Bablok regression and Bland-Altman analysis. Results:The linear range of ICP-MS standard curve was 0 - 300 μg/L. There was a good linear correlation between iodine concentration value and iodine response value, and the correlation coefficient range was 0.999 8 to 0.999 9. The detection limit of the ICP-MS method was 1.96 μg/L. The relative standard deviation ( RSD) ranged from 0.2% to 1.4% and from 0.4% to 1.8% for intra and inter-batch precision tests of serum samples. The recovery rate ranged from 90.44% to 108.71%. The correlation analysis of 88 serum samples showed that there was a good correlation between the two methods ( r = 0.934, P < 0.05), and the intra-class correlation coefficient was 0.932. The results of Passing-Bablok regression showed that there was no significant difference between the two methods ( P > 0.05). Bland-Altman diagram suggested that the results of the two methods were consistent. Conclusions:ICP-MS method has low detection limit, high precision and accuracy. ICP-MS method is simple, rapid, easy and suitable for determination of iodine in large quantities of serum samples. The results of the two methods for determining serum iodine are consistent.