Identification of Organic Iodine Compounds and Their Transformation

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Identification of Organic Iodine Compounds and their Transformation Products in Edible Iodized Salt using Liquid Chromatography-High Resolution Mass Spectrometry Lifen Yun, Yue'e Peng, Qing Chang, Qingxin Zhu, Wei Guo, and Yanxin Wang J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.7b01759 • Publication Date (Web): 16 Jun 2017 Downloaded from http://pubs.acs.org on June 19, 2017

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Journal of Agricultural and Food Chemistry

Identification of Organic Iodine Compounds and their Transformation Products in Edible Iodized Salt using Liquid Chromatography-High Resolution Mass Spectrometry Lifen Yun† , Yue’e Peng*, †, ‡, Qing Chang‡, Qingxin Zhu†, Wei Guo‡, Yanxin Wang‡ †

‡

Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074, PR China State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences , Wuhan, 430074, PR China

Corresponding Author E-mail: [email protected]

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ACS Paragon Plus Environment


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ABSTRACT

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The consumption of edible iodized salt is a key strategy to control and eliminate iodine deficiency disorders

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worldwide. We herein report the identification of the organic iodine compounds present in different edible

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iodized salt products using liquid chromatography combined with high resolution mass spectrometry. A total

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of 38 organic iodine compounds and their transformation products (TPs) were identified in seaweed iodine

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salt from China. Our experiments confirmed that the TPs were generated by the replacement of I atoms from

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organic iodine compounds with Cl atoms. Furthermore, the organic iodine compound contents in 4 seaweed

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iodine salt samples obtained from different manufactures were measured, with significant differences in

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content being observed. We expect that the identification of organic iodine compounds in salt will be

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important for estimating the validity and safety of edible iodized salt products.

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KEYWORDS: organic iodine compound, identification, LC-HRMS, iodized salt, seaweed iodine

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INTRODUCTION

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Iodine is an essential element for mammalian life, as it is a component of thyroid hormones, such as

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thyroxine (T4) and triiodothyronine (T3). Indeed, United Nations Children’s Fund (UNICEF), International

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Council for Control of iodine deficiency disorders (ICCIDD), and the World Health Organization (WHO)

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recommend daily iodine intakes of 90 µg for preschool children (0–59 months), 120 µg for schoolchildren

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(6–12 years), 150 µg for adolescents (>12 years) and adults, and 250 µg for pregnant and lactating women1.

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This recommended daily intake is particularly important, as an iodine deficiency can occur at any stage of

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life, especially the pregnant women and young children2–4, and can lead to a number of adverse effects5.

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Indeed, in 2007, the WHO estimated that approximately 2 billion individuals worldwide have an insufficient

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iodine intake6.

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To ensure sufficient intakes of iodine by the population, in 1994 the WHO and UNICEF recommended

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universal salt iodization (USI) as a safe, cost-effective, and sustainable strategy7. Universal salt iodization

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(USI) involves the addition of potassium iodate (KIO3) or potassium iodide (KI) to edible salt. In addition to

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KIO3, a new natural seaweed iodide was recently proposed in China for the addition to edible salt8, where

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the major component was organic iodine. When compared with inorganic iodine, the use of seaweed-based

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iodide can be considered safer9–14 and more efficient14–15. As such, the identification of the organic iodine

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compounds present would provide basic data for further research into iodine supplementation. Iodine

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speciation is an area that attracts considerable attention. Many researchers have studied iodine speciation for

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environmental, biological and nutrition fileds16, such as iodized salt17-19. However, the majority of studies

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carried out to date into iodized salts have focused on the content20–22 and stability23–25 of inorganic iodine

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compounds, such as iodides and iodates, with organic iodine compounds receiving little attention. In this

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context, our group recently developed a method for the identification of the organic iodine compounds in

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seaweed26. The method has two major features; first, it can easily discover and locate non-target compounds

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containing iodine by detecting their specific fragment ion, I− (m/z 126.9039), allowing selective

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identification of unknown organic iodine compounds in low concentrations and complex samples. Second,

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the retention time was regarded as an important parameter in detecting organic iodine compounds and

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distinguishing them from impurities with the same mass26. Thus, we herein report our study into the 3



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identification of the unknown organic iodine compounds present in edible iodized salt and their possible

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transformation products (TPs) using a combination of liquid chromatography and high resolution mass

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spectrometry (LC-HRMS).

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MATERIALS AND METHODS

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Chemicals and reagents

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LC-MS grade methanol, acetic acid, and acetonitrile were acquired from Fisher Scientific. Ultrapure water

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with a resistivity of 18.2 MΩ cm−1 was generated using a Milli-Q® ultrapure water system (Millipore). Solid

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phase extraction (SPE) cartridges (SupelcleanTM LC-18, 6 mL, 0.5 g) were purchased from Sigma-Aldrich.

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Nitrogen gas (99.999%) was purchased from the Heyuan Gas Company (Hubei, China).

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Samples and pretreatment

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Commercially available edible seaweed iodine salt, deep well iodized salt, and iodized rock salt were

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purchased from supermarkets in Wuhan, Chongqing, and Chengdu (China), respectively, while non-iodized

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salt samples produced in America, Italy, Britain, and France, were purchased from American supermarket

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and online. A sample of each salt (~30 g) was dissolved in ultrapure water (100 mL) in a PET bottle and the

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resulting solutions were purified and enriched by solid-phase extraction (SPE) according to the following

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procedure. Samples were pumped through a SPE cartridge (SupelcleanTM LC-18, 6 mL, 0.5 g) at a flow rate

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of ~1 mL/min. Firstly, methanol (2 mL) and ultrapure water (2 mL) were added to activate the SPE cartridge.

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The sample solution (100 mL) was then loaded onto the SPE column, which was subsequently eluted with

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ultrapure water (50 mL) to reduce the salinity. Finally, methanol (1.5 mL) was added to the column and the

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sample was eluted into a 1.5 mL vial for analysis by LC-HRMS.

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Instrumentation

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Ultra high performance liquid chromatography (UHPLC, UltiMate 3000, Dionex) combined with mass

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spectrometry (MS, Q ExactiveTM Hybrid Quadrupole-OrbitrapTM, Thermo Scientific, Bremen, Germany)

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was employed throughout this study. UHPLC separation was performed using a Hypersil GoldTM C18 4


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column (3.0 µm particle size, 3 mm × 150 mm, Thermo Fisher) at a column temperature of 40 °C. The

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mobile phases employed were water containing 0.2% acetic acid (solvent A) and acetonitrile (solvent B).

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Separation was carried out at a flow rate of 0.25 mL min−1 using the following elution gradient: 10%

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acetonitrile for 2 min, linear increase to 60% acetonitrile over 2 min, 60% acetonitrile for 4 min, return to

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10% acetonitrile (initial conditions) over 2 min, and hold at 10% acetonitrile for a further 2 min for

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re-equilibration (total run time, 12 min). For all measurements, the autosampler temperature was maintained

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at 10 °C and a sample injection volume of 5 µL was employed. Detection was carried out by mass

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spectrometry using a heated electrospray ionization (HESI) source in the negative mode in addition to the

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following parameters: Spray voltage, −3.2 kV; S-lens RF level, 50%; capillary temperature, 300 °C; mass

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resolution, 70000; and normalized collision energy (NCE), 35. All other parameters were set as their default

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values. The data were processed using XcaliburTM 2.1 software (Thermo Scientific). The instrument were

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externally calibrated for a mass range of 50-2000 using a solution containing caffeine, MRFA, Ultramark

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1621, n-butylamine for positive mode and solution containing twelve alkyl sodium sulfate, sodium

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taurocholate, Ultramark 1621 for negative mode.

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Identification of the organic iodine compounds

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The process employed for the identification of organic iodine was similar to the procedure previously

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established26. Firstly, A m/z width of 25 was analyzed in the negative t-MS2 and full MS scan mode, and

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then accurate mass of all possible precursor ions of organic iodine compounds were selected. Next, the

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possible precursor ions were confirmed using the negative t-MS2 scan mode. Finally, possible elemental

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compositions and structures of organic iodine compounds were obtained according to the accurate mass and

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ChemSpider database. It should be noted that, in the study, only compounds that can be absorbed on C18

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SPE column and desorbed by methanol solvent were analyzed by LC-HRMS.

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RESULTS AND DISCUSSION

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Accurate masses and molecular formulae of the organic iodine ions

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According to the identification method above, all accurate masses of organic iodine compounds were 5



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obtained. Subsequently, all possible molecular formulae for the organic iodine compounds were calculated

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from their accurate masses using Xcalibur software, which allowed calculation of the basic elements C, H, O,

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N, and I within a 5 ppm mass tolerance. However, a number of organic iodine compounds exhibited isotopic

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peaks (i.e., [M]− and [M+2]−), the ratios of which (3:1, 3:2, or 1:1) were roughly consistent with the presence

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of one, two, or three Cl atoms in the structures. As such, Cl was incorporated into the molecular formulae

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calculations using the obtained accurate masses.

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The peaks at m/z 218.9038 and 246.9256 (Rt = 10.07 min) were excluded from the calculations, as they

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were also present in the ultrapure water sample. In addition, precursor ions at m/z 172.9096 and 186.9245

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exhibited two extraction peaks in the chromatograms at different retention times, thus indicating that they

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may be isomers. Finally, 38 organic iodine compounds present in the Chinese seaweed iodine salt and 5

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organic iodine compounds present in the American non-iodized salt were identified. However, no organic

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iodine compounds were identified in the deep well iodized salt or iodized rock salt. The compound of m/z

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246.9256 (Rt = 9.2 min) identified in this paper matches the structure of 2-iodobenzoic acid which has been

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reported in seaweeds in our previous work26. Herein, the organic iodine additives in edible seaweed salt are

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the extracts of seaweed. Therefore, the compound most likely come from seaweed. Figure 1 shows the

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extracted ion chromatograms (EIC), retention times (Rt), accurate masses and proposed molecular formulae

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for the identified organic iodine compounds, and their mass spectra in the target-MS2 scan mode are shown

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in Figure S1. Some of identified organic iodine compounds were also observed in the positive full MS scan

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mode, and their EIC are shown in Figure S2.

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Possible transformation products (TPs) of the organic iodine compounds present in the salt samples

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Based on the proposed molecular formulae of the identified organic iodine compounds from seaweed iodine

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salt, it appears that a substitution reaction may occur wherein an I atom is replaced with a Cl atom. In this

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context, Table 1 lists the corresponding organic iodine compounds and their respective TPs following

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incorporation of a Cl atom. For example, for the organic iodine compounds with m/z values of 488.9955

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(9.43 min), 580.9313 (9.96 min), and 672.8658 (10.64 min), the proposed molecular formulae are

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C14H21O3N4Cl2I, C14H21O3N4ClI2, and C14H21O3N4I3, respectively. Considering the high concentration of 6


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chloride in salt in addition to the relative activities of the three halogenic RX species (i.e., RI > RBr > RCl),

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and the leaving group ability of the halogen anions (i.e., I− > Br− > Cl−), the replacement of an I atom with a

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Cl atom (mass difference = 91.9356) was considered likely. As such, it was proposed that the compound

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with molecular formula C14H21O3N4Cl3 (m/z 397.0596) may also exist, and indeed, upon further

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examination of the MS results, a signal corresponding to this compound was observed at 9.01 min. Figure 2

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shows the EICs and mass spectra of these four related compounds. A similar substitution reaction was

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observed for the American non-iodized salt sample, where the three Cl-containing organic compounds with

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the molecular formulae C10H7O2N3Cl (Rt = 8.67 min), C20H29O4Cl (Rt = 11.24 min), and C22H37O4N2Cl (Rt =

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9.22 min)(See S3) were observed following substitution reactions of C10H7O2N3I, C20H29O4I, and

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C22H37O4N2I, respectively.

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To confirm the substitution of I atoms with Cl atoms in the organic iodine compounds present in the salt

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samples, a simulation experiment was conducted. More specifically, T3 (triiodothyronine, C15H12I3NO4) and

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T4 (thyroxine, C15H11I4NO4) were added to the deep well iodized salt solution, which was then stored under

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ambient conditions for 15 d, and the possible TPs of T3 and T4 were identified from the salt samples both

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before and after doping. Thus, Figure 3 shows the extracted ion chromatograms of T3 and T4 and their

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possible TPs, i.e., C15H12ClI2NO4 and C15H11ClI3NO4.

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As shown in Figure 3, the TPs of T3 and T4 were clearly visible in the salt samples after 15 d, thus

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confirming the transformation of organic iodine compounds into their corresponding chlorine analogs during

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salt processing. It should therefore be noted that the toxicity of a number of chlorinated organic compounds

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to humans and animals has been previously reported27–29. As such, the substitution reaction of iodine with

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chlorine not only reduces the effectiveness of iodine incorporation, but may also result in the formation of

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toxic substances. Therefore, the safety and efficiency of such edible iodized salt samples should be further

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investigated. However, these experiments are outside the scope of this study.

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Variation in the numbers and contents of organic iodine compounds in different salt samples

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The numbers and contents of organic iodine compounds present in 4 different seaweed iodine salt samples

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produced by 4 different manufacturers from the Hubei province were estimated by computing their peak 7



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areas from the EICs. Figure 4 shows the contents of the various identified organic iodine compounds present

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in the salt samples, with significant differences being observed between samples. For example, 38 organic

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iodine compounds were identified in sample 1, while only 19, 11, and 9 of these compounds were present in

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the other three samples. Furthermore, the contents of the same organic iodine compounds differed slightly

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between samples. For example, the relative peak area of C14H21O3N4ClI2 (compound 24) was 2315 × 104 in

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sample 1, but was only 297 × 104, 93 × 104, and 46 × 104 in samples 2, 3, and 4, respectively. These results

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therefore indicate that significant variations in the numbers and contents of organic iodine compounds were

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present in the seaweed iodine salts obtained from different manufactures.

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A total of 38 organic iodine compounds were firstly identified in seaweed iodine salt from China, while 5

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organic iodine compounds were identified in non-iodized salt from America, using a combination of liquid

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chromatography and high resolution mass spectrometry, which provided valuable information regarding

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their retention times, accurate masses, and possible molecular formulae. Through careful examination of the

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proposed molecular formulae of these organic iodine species, we found that the replacement of I atoms with

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Cl atoms occurred during salt processing, thus affecting the safety and efficiency of these iodized salts.

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Furthermore, we confirmed that the distribution of organic iodine compounds in seaweed iodine salt samples

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varied between manufacturers. We expect that these results will be important, as the identification of organic

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iodine compounds and their corresponding transformation products in edible iodized salt is essential for

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subsequent estimation of the validity and safety of iodized salts to produce improved iodine supplements.

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Abbreviations Used

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IDD, iodine deficiency disorders; LC-HRMS, liquid chromatography combined with high resolution mass

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spectrometry; TPs, transformation products; USI, universal salt iodization; SPE, solid phase extraction; EIC,

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extracted ion chromatograms.

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Funding

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The project is supported by the NSFC (No. 21305130 and No. 41521001).

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Supporting Information

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Mass spectra of identified organic iodine compounds acquired in negative t-MS2 scan mode (Figure S1).

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Extracted ion chromatograms, retention times, accurate masses, and proposed molecular formulae of the

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organic iodine compounds observed in the positive full MS scan mode (Figure S2). Extracted ion

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chromatograms, retention time, accurate mass and possible molecular formulas of TPs in non-iodized salt

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(America) in full MS scan mode (Figure S3).

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References

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(1) World Health Organization. IDD and their control, and global progress in their elimination. In

184

Assessment of iodine deficiency disorders and monitoring their elimination : a guide for programme

185

managers, 3rd ed.; Publisher: World Health Organization, Geneva, Switzerland, 2007; pp 6-16.

186 187 188 189 190 191 192 193 194 195

(2) Obican, S. G.; Jahnke, G. D.; Soldin, O. P.; Scialli, A. R. Teratology public affairs committee position paper: iodine deficiency in pregnancy. Birth Defects Res A Clin Mol Teratol. 2012, 94, 677-682. (3) Zimmermann, M. B. Iodine deficiency in pregnancy and the effects of maternal iodine supplementation on the offspring: a review. Am J Clin Nutr. 2009, 89, 668S-672S. (4) Zimmermann, M. B. The adverse effects of mild-to-moderate iodine deficiency during pregnancy and childhood: a review. Thyroid. 2007, 17, 829-835. (5) Zimmermann, M. B.; Jooste, P. L.; Pandav, C. S. Iodine-deficiency disorders. Lancet. 2008, 372, 1251-1262. (6) de Benoist, B.; McLean, E.; Andersson, M.; Rogers, L. Iodine deficiency in 2007: global progress since 2003. Food Nutr Bull. 2008, 29, 195-202.

196

(7) WHO; UNICEF. World summit for children mid-decade goal: iodine deficiency disorders.

197

UNICEF-WHO Joint Committee on Health Policy. Publisher: World Health Organization, Geneva,

198

Switzerland. 1994, JCHPSS/94/2.7.

9


Journal of Agricultural and Food Chemistry 199 200 201 202 203 204

Page 10 of 19

(8) Liu, Z. B.; Hong, G. Q.; Kong, Q. X. The research and development of seaweed iodine salt. Sea-Lake Salt Chem Ind. 1997, 26, 4-5. (9) Gu, J.; Sun, P.; Zhuang, G. Study on the chronic toxicity evaluation of biological organic iodine in kelp. Food Res Dev. 2003, 24, 48-49. (10) Lin, X.; Zhao, Y.; Yao, P.; Guo, D. Effect of DIT on cytokines secretion in cultured human thyrocytes. Chin J Ctrl Endem Dis. 2007, 22, 343-345.

205

(11) Liu, D.; Lin, X.; Yu, F.; Zhang, M. Contrastive study on the effect of 3,5-diiodotyrosine and potassium

206

iodide on myocardial ATPase in hyperthyroidism wistar rats. Chin J Endemiol. 2015, 34, 646-649.

207

(12) Zhao, Y.; Lin, X.; Guo, D.; Wang, S.; Liu, X. Effect of DIT on proliferation of human thyrocytes in

208 209 210

vitro. Chin J Public Health. 2007, 23, 427-428. (13) Chi, Y. The evaluation of organic iodine in kelp supplementing iodine on animal. J Chin Inst Food Sci Tech. 2002, 2, 37-42.

211

(14) Liu, D.; Lin, X.; Yu, F.; Zhang, M.; Chen, H.; Bao, W.; Wang, X. Effects of 3, 5-diiodotyrosine and

212

potassium iodide on thyroid function and oxidative stress in iodine-excess wistar rats. Biol Trace Elem

213

Res. 2015, 168, 447-452.

214 215 216 217 218 219 220 221

(15) Tang, X. Studies on the purification of bio-active iodine in kelp and the complementing effect on mice. Master’s thesis, Shandong Normal University, 2001. (16) Moreda-Piñeiro, A.; Romarís-Hortas, V.; Bermejo-Barrera, P. A review on iodine speciation for environmental, biological and nutrition fields. J Anal At Spectrom. 2011, 26, 2107-2152. (17) Dasgupta, P. K.; Liu, Y.; Dyke, J. V. Iodine nutrition: iodine content of iodized salt in the United States. Environ Sci Technol. 2008, 42, 1315-1323. (18) Shabani, A. M. H.; Ellis, P. S.; McKelvie, I. D. Spectrophotometric determination of iodate in iodised salt by flow injection analysis. Food Chem. 2011, 129, 704-707.

10


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222

(19) Huang, Z.; Subhani, Q.; Zhu, Z.; Guo, W.; Zhu, Y. A single pump cycling-column-switching technique

223

coupled with homemade high exchange capacity columns for the determination of iodate in iodized

224

edible salt by ion chromatography with UV detection. Food Chem. 2013, 139, 144-148.

225 226 227 228 229 230 231 232 233 234 235 236

(20) Kumar, S. D.; Maiti, B.; Mathur, P. K. Determination of iodate and sulphate in iodized common salt by ion chromatography with conductivity detection. Talanta. 2001, 53, 701-705. (21) Wang, T.; Zhao, S.; Shen, C.; Tang, J.; Wang, D. Determination of iodate in table salt by transient isotachophoresis–capillary zone electrophoresis. Food Chem. 2009, 112, 215-220. (22) Rebary, B.; Paul, P.; Ghosh, P. K. Determination of iodide and iodate in edible salt by ion chromatography with integrated amperometric detection. Food Chem. 2010, 123, 529-534. (23) Chavasit, V.; Malaivongse, P.; Judprasong, K. Study on stability of iodine in iodated salt by use of different cooking model conditions. J Food Comp Anal. 2002, 15, 265-276. (24) Diosady, L. L.; Alberti, J. O.; Venkatesh Mannar, M. G.; Stone, T. G. Stability of iodine in iodized salt used for correction of iodine-deficiency disorders. Food Nutr Bull. 1997, 18, 388-396. (25) Diosady, L. L.; Alberti, J. O.; Venkatesh Mannar, M. G.; FitzGerald, S. Stability of iodine in iodized salt used for correction of iodine-deficiency disorders. II. Food Nutr Bull. 1998, 19, 240-250.

237

(26) Yang, Y.; Peng, Y.; Chang, Q.; Dan, C.; Guo, W.; Wang, Y. Selective identification of organic iodine

238

compounds using liquid chromatography–high resolution mass spectrometry. Anal Chem. 2016, 88,

239

1275-1280.

240 241

(27) Henschler, D. Toxicity of chlorinated organic compounds: effects of the introduction of chlorine in organic molecules. Angew Chem Int Ed Engl. 1994, 33, 1920-1935.

242

(28) Smith, A. D.; Bharath, A.; Mallard, C.; Orr, D.; Smith, K.; Sutton, J. A.; Vukmanich, J.; McCarty, L. S.;

243

Ozburn, G. W. The acute and chronic toxicity of ten chlorinated organic compounds to the American

244

flagfish (Jordanella floridae). Arch Environ Contam Toxicol. 1991, 20, 94-102.

11



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(29) Huang, B.; Lei, C.; Wei, C.; Zeng, G. Chlorinated volatile organic compounds (Cl-VOCs) in

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environment-sources, potential human health impacts, and current remediation technologies. Environ

247

Int. 2014, 71, 118-138.

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Figure captions

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Figure 1. Extracted ion chromatograms, retention times, accurate masses, and proposed molecular formulae

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of the organic iodine compounds observed in the negative full MS scan mode. (a) The 38 organic iodine

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compounds present in the Chinese seaweed iodine salt, and (b) the 5 organic iodine compounds present in

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the American non-iodized salt.

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Figure 2. (a) Extracted ion chromatograms of the peaks with m/z values of 397.0593, 488.9955, 580.9313,

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and 672.8658; and (b) mass spectra of the four compounds recorded in negative full MS scan mode.

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Figure 3. Extracted ion chromatograms of T3 (m/z 649.7818), T4 (m/z 775.6783), [C15H11ClI2NO4]− (m/z

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557.8460), and [C15H10ClI3NO4]− (m/z 683.7427) in negative full MS scan mode, (a) at day 0, and (b) after

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15 d.

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Figure 4. Organic iodine contents of different seaweed iodine salt samples.

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Tables Table 1. Correlation of Select Organic Iodine Compounds in Seaweed Iodine Salt Accurate mass of Correlation Rt (min) Possible molecular formula [M−H]− 8.21 281.0122 C9H13N4Cl3 8.51 372.9473 C9H13N4Cl2I 8.85 464.8837 C9H13N4ClI2 8.22 305.0567 C11H16O2N4Cl2 8.51 396.9921 C11H16O2N4ClI 8.85 488.9278 C11H16O2N4I2 8.93 353.0333 C12H17O2N4Cl3 9.35 444.9694 C12H17O2N4Cl2I 9.86 536.9047 C12H17O2N4ClI2 10.52 628.8402 C12H17O2N4I3 9.02 337.0384 C12H17ON4Cl3 9.43 428.9745 C12H17ON4Cl2I I → Cl C12H17ON4ClI2 9.96 520.9091 (91.9356) C12H17ON4I3 10.64 612.8448 9.01 373.0151 C12H18ON4Cl4 9.43 464.9512 C12H18ON4Cl3I 9.96 556.8864 C12H18ON4Cl2I2 10.64 648.8215 C12H18ON4ClI3 9.01 397.0593 C14H21O3N4Cl3 9.43 488.9955 C14H21O3N4Cl2I C14H21O3N4ClI2 9.96 580.9313 10.64 672.8658 C14H21O3N4I3 7.68 593.2787 C28H49O3N4Cl3 9.43 685.2147 C28H49O3N4Cl2I 9.96 777.1491 C28H49O3N4ClI2

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Identification of Organic Iodine Compounds and Their Transformation

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