Methodological validation: a method for determination of iodine in serum by inductively coupled plasma mass spectrometry.

Abstract

Objective To validate a developing method for determination of iodine in serum by inductively coupled plasma mass spectrometry (ICP-MS). Methods Ammonium chloride, ethanolamine, ascorbic acid and water were mixed at a certain ratio, adding ethanol as sensitization, to dilute samples in the ratio of 1 ∶ 20, and then the diluted samples were analyzed by ICP-MS. Re was used as the internal standard. Serum samples were from 8 different individuals. After combining, they were divided into 4 groups, control group and low, medium and high iodine groups. Iodine groups were added with potassium iodide (100 mg/L), iodine standard solution 1.5, 9.0, 15.0 μl. The methodological evaluation of this method was done through standard curve linearity, sample detection limit, precision, recovery and accuracy in determining biological sample. And the results were compared with the current serum iodine arsenic cerium catalytic spectrophotometry standard method (WS/T 572-2017). Results The linear range of the calibration curve was 0 - 300 μg/L and the linear correlative coefficients of the standard curve were 0.999 8 - 1.000 0. The detection limit was 0.38 μg/L (the sample amount was 0.2 ml). The coefficients of variation (CV) were all below 2% for 4 serum samples in precision. The recovery rate was in a range of 95.8% - 108.5%. No significant difference was found between the results of the 15 serum samples determined by the standard method and this new method (t = 1.139, P > 0.05). Conclusions The newly developed method in determination of iodine in serum by ICP-MS, has wide linear range, high sensitivity, good precision, and wide applicability. It is suitable for application in determining serum iodine. Key words: Iodine; Inductively coupled plasma mass spectrometry; Serum