Affiliation:
1. Key Laboratory of Marine Resource Chemistry and Food Technology, Ministry of Education, College of Biotechnology and College of Chemical Engineering and Materials Science, Tianjin University of Science and Technology, Tianjin 300457, China
2. China Salt Engineering Technology Research Institute Co., Ltd., Tianjin 300457, China
3. Hubei Yixin Salt Industry Technology Research Institute Co., Ltd, Xiaogan 432400, China
Abstract
The analysis of iodine content in kelp is mainly focused on determining total iodine content, which lacks a rapid and sensitive analytical method for iodine species corresponding to iodate, iodide, monoiodotyrosine (MIT), and diiodo-tyrosine (DIT). Based on exploring the pretreatment methods of enzymatic hydrolysis of kelp, a rapid determination method of high-performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICP-MS) for different iodine species existed in kelp samples was established. The pretreatment method is trypsin hydrolysis of kelp samples treated at 50°C for 10 hours, then the extraction solution was obtained by centrifugation, and filtration was proved for the first time. A high-efficiency separation anion-exchange column (Dionex IonPac AS-14) for iodate, iodide, MIT, and DIT with 0.1 mol·L−1(NH4)2CO3 solution at pH = 9 as a mobile phase, a flow rate of 0.8 mL·min−1 for the first 1500 s, and 1.2 mL·min−1 for the last 1800 s was confirmed. The linear ranges of the standard calibrations on four iodine species are 1.0–150 μg·L−1, and the detection limits are 1.62, 1.02, 1.59, and 2.55 μg·L−1, respectively, while the RSD values of four iodine species are all less than 2%. Under the optimized conditions, the proposed method was successfully applied for the speciation analysis of iodine in kelp samples.
Funder
National Natural Science Foundation of China