Speciation analysis of iodine in seaweed: optimisation of extraction procedure and chromatographic separation
Ana Jerše
A B , Heidi Amlund A , Susan L. Holdt A and Jens J. Sloth A *
A National Food Institute, Technical University of Denmark, Kemitorvet, Building 201, 2800 Kgs. Lyngby, Denmark.
B Present address: Agricultural Institute of Slovenia, Hacquetova ulica 17, 1000 Ljubljana, Slovenia.
Environmental Chemistry - https://doi.org/10.1071/EN22133
Submitted: 9 December 2022 Accepted: 17 April 2023 Published online: 4 May 2023
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing.
Environmental context. Seaweed is a good natural dietary source of iodine and some types of seaweed are rich in iodine. Iodine has a diverse chemistry in seaweeds and may exist as different chemical species; however, the occurrence and identity of the individual species are still not fully elucidated. Hence, development of sensitive and selective iodine speciation methods for studies of iodine chemistry and biotransformation in seaweeds are needed.
Rationale. Iodine is an essential element required for human health and metabolism. Seafood and especially seaweed can accumulate iodine to high amounts. Iodine may exist in different chemical forms (species) in seaweeds.
Methodology. The present study describes the development and optimisation of a method for iodine speciation analysis in seaweed based on high performance liquid chromatography–inductively coupled plasma–mass spectrometry (HPLC-ICP-MS). The extraction procedure was conducted in two steps, pancreatic enzymatic extraction followed by alkaline extraction with tetramethylammonium hydroxide for optimum extraction efficiency without compromising species integrity.
Results and discussion. Total iodine and iodine species were determined in a range of brown (6 samples), red (6 samples) and green (3 samples) seaweeds. A large variation in the total iodine content of the different seaweeds was observed (33–5611 µg g–1 dry weight) with the highest levels encountered in brown seaweed. Iodine speciation analysis revealed differences in the speciation profile of the different types of seaweed. In all seaweeds iodide was the predominant species, and minor contents of MIT (monoiodotyrosine) and DIT (diiodotyrosine) were found in most seaweeds. Furthermore, peaks originating from six unknown iodine-containing species were observed in the chromatograms, especially in red and green seaweeds, while less abundant in brown seaweeds. The speciation method presented here will be valuable in future studies on iodine speciation in seaweed and an important tool for the investigation of iodine speciation and biotransformation in marine algae.
Keywords: alkaline extraction, DIT, enzymatic extraction, HPLC-ICPMS, iodide, macroalgae, MIT, total iodine.
References
Aakre I, Solli DD, Markhus MW, Mæhre HK, Dahl L, Henjum S, Alexander J, Korneliussen P-A, Madsen L, Kjellevold M (2021). Commercially available kelp and seaweed products – valuable iodine source or risk of excess intake?. Food & Nutrition research 65, 7584| Commercially available kelp and seaweed products – valuable iodine source or risk of excess intake?.Crossref | GoogleScholarGoogle Scholar |
Aquaron R, Delange F, Marchal P, Lognoné V, Ninane L (2002). Bioavailability of seaweed iodine in human beings. Cellular and Molecular Biology (Noisy-le-Grand, France) 48, 563–569.
Banach JL, Hoek-van den Hil EF, van der Fels-Klerx HJ (2020). Food safety hazards in the European seaweed chain. Comprehensive Reviews in Food Science and Food Safety 19, 332–364.
| Food safety hazards in the European seaweed chain.Crossref | GoogleScholarGoogle Scholar |
Biancarosa I, Belghit I, Bruckner CG, Liland NS, Waagbø R, Amlund H, Heesch S, Lock E-J (2018). Chemical characterization of 21 species of marine macroalgae common in Norwegian waters: benefits of and limitations to their potential use in food and feed. Journal of the Science of Food and Agriculture 98, 2035–2042.
| Chemical characterization of 21 species of marine macroalgae common in Norwegian waters: benefits of and limitations to their potential use in food and feed.Crossref | GoogleScholarGoogle Scholar |
CEN (2017) ‘European Standard EN 17050:2017. Animal feeding stuffs: Methods of sampling and analysis - Determination of iodine in animal feed by ICP-MS.’ (The European Committee for Standardization: Brussels, Belgium)
Cherry P, O’Hara C, Magee PJ, McSorley EM, Allsopp PJ (2019). Risks and benefits of consuming edible seaweeds. Nutrition Reviews 77, 307–329.
| Risks and benefits of consuming edible seaweeds.Crossref | GoogleScholarGoogle Scholar |
(2014). Scientific Opinion on Dietary Reference Values for iodine. EFSA Journal 12, 3660
| Scientific Opinion on Dietary Reference Values for iodine.Crossref | GoogleScholarGoogle Scholar |
European Commission (2017) ‘Food from the ocean.’ (Scientific Opinion No. 3/2017 Publications Office of the European Union: Luxembourg) Available at https://ec.europa.eu/research/sam/pdf/sam_food-from-oceans_ report.pdf [accessed 8 December 2022]
FAO, WHO (2022) ‘Report of the expert meeting on food safety for seaweed – Current status and future perspectives, Rome, 28–29 October 2021’. Food Safety and Quality Series No. 13. Food and Agriculture Organization, Rome, Italy.
| Crossref |
Feldmann J, Raab A, Krupp EM (2018). Importance of ICPMS for speciation analysis is changing: future trends for targeted and non-targeted element speciation analysis. Analytical and Bioanalytical Chemistry 410, 661–667.
| Importance of ICPMS for speciation analysis is changing: future trends for targeted and non-targeted element speciation analysis.Crossref | GoogleScholarGoogle Scholar |
Goessler W, Kuehnelt D, Schlagenhaufen C, Slejkovec Z, Irgolic KJ (1998). Arsenobetaine and other arsenic compounds in the National Research Council of Canada Certified Reference Materials DORM 1 and DORM 2. Journal of Analytical Atomic Spectrometry 13, 183–187.
| Arsenobetaine and other arsenic compounds in the National Research Council of Canada Certified Reference Materials DORM 1 and DORM 2.Crossref | GoogleScholarGoogle Scholar |
Gómez-Jacinto V, Arias-Borrego A, García-Barrera T, Garbayo I, Vílchez C, Gómez-Ariza JL (2010). Iodine speciation in iodine-enriched microalgae Chlorella vulgaris. Pure and Applied Chemistry 82, 473–481.
| Iodine speciation in iodine-enriched microalgae Chlorella vulgaris.Crossref | GoogleScholarGoogle Scholar |
Han X, Cao L, Cheng H, Liu J, Xu Z (2012). Determination of iodine species in seaweed and seawater samples using ion-pair reversed phase high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry. Analytical Methods 4, 3471–3477.
| Determination of iodine species in seaweed and seawater samples using ion-pair reversed phase high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry.Crossref | GoogleScholarGoogle Scholar |
Hou XL, Chai CF, Qian QF, Yan XJ, Fan X (1997). Determination of chemical species of iodine in some seaweeds (I). Science of the Total Environment 204, 215–221.
| Determination of chemical species of iodine in some seaweeds (I).Crossref | GoogleScholarGoogle Scholar |
Jerše A, Kutscher D, Fischer C, Sloth JJ (2020) Determination of iodine-containing species in seaweed using IC-ICP-MS. Thermo Scientific Application note 44475. Available at https://appslab.thermofisher.com/Account/Login?returnUrl=%2FApp%2F4510%2Fiodine-speciation-seaweed
Jerše A, Amlund H, Rasmussen RR, Sloth JJ (2021). Iodine determination in animal feed by inductively coupled plasma mass spectrometry – results of a collaborative study. Food Additives & Contaminants: Part A 38, 261–267.
| Iodine determination in animal feed by inductively coupled plasma mass spectrometry – results of a collaborative study.Crossref | GoogleScholarGoogle Scholar |
Kreissig KJ, Hansen LT, Jensen PE, Wegeberg S, Geertz-Hansen O, Sloth JJ (2021). Characterisation and chemometric evaluation of 17 elements in ten seaweed species from Greeland. PLoS One 16, e0243672
| Characterisation and chemometric evaluation of 17 elements in ten seaweed species from Greeland.Crossref | GoogleScholarGoogle Scholar |
Lüning K, Mortensen L (2015). European aquaculture of sugar kelp (Saccharina latissima) for food industries: Iodine content and epiphytic animals as major problems. Botanica Marina 58, 449–455.
| European aquaculture of sugar kelp (Saccharina latissima) for food industries: Iodine content and epiphytic animals as major problems.Crossref | GoogleScholarGoogle Scholar |
Morais T, Inácio A, Coutinho T, Ministro M, Cotas J, Pereira L, Bahcevandziev K (2020). Seaweed potential in the Animal Feed: A Review. Journal of Marine Science and Engineering 8, 559
| Seaweed potential in the Animal Feed: A Review.Crossref | GoogleScholarGoogle Scholar |
Moreda-Piñeiro A, Romarís-Hortas V, Bermejo-Barrera P (2011). A review on iodine speciation for environmental, biological and nutrition fields. Journal of Analytical Atomic Spectrometry 26, 2107–2152.
| A review on iodine speciation for environmental, biological and nutrition fields.Crossref | GoogleScholarGoogle Scholar |
Monteiro MS, Sloth JJ, Holdt S, Hansen M (2019). Analysis and Risk Assessment of Seaweed. EFSA Journal 17, e170915
| Analysis and Risk Assessment of Seaweed.Crossref | GoogleScholarGoogle Scholar |
Roleda MY, Skjermo J, Marfaing H, Jónsdóttir R, Rebours C, Gietl A, Stengel DB, Nitschke U (2018). Iodine content in bulk biomass of wild-harvested and cultivated edible seaweeds: Inherent variations determine species-specific daily allowable consumption. Food Chemistry 254, 333–339.
| Iodine content in bulk biomass of wild-harvested and cultivated edible seaweeds: Inherent variations determine species-specific daily allowable consumption.Crossref | GoogleScholarGoogle Scholar |
Romarís-Hortas V, Bermejo-Barrera P, Moreda-Piñeiro A (2012). Development of anion-exchange/reversed-phase high performance liquid chromatography-inductively coupled plasma-mass spectrometry methods for the speciation of bio-available iodine and bromine from edible seaweed. Journal of Chromatography A 1236, 164–176.
| Development of anion-exchange/reversed-phase high performance liquid chromatography-inductively coupled plasma-mass spectrometry methods for the speciation of bio-available iodine and bromine from edible seaweed.Crossref | GoogleScholarGoogle Scholar |
Romarís-Hortas V, Bermejo-Barrera P, Moreda-Piñeiro A (2013). Ultrasound-assisted enzymatic hydrolysis for iodinated amino acid extraction from edible seaweed before reversed-phase high performance liquid chromatography-inductively coupled plasma-mass spectrometry. Journal of Chromatography A 1309, 33–40.
| Ultrasound-assisted enzymatic hydrolysis for iodinated amino acid extraction from edible seaweed before reversed-phase high performance liquid chromatography-inductively coupled plasma-mass spectrometry.Crossref | GoogleScholarGoogle Scholar |
Shah M, Wuilloud RG, Kannamkumarath SS, Caruso JA (2005). Iodine speciation studies in commercially available seaweed by coupling different chromatographic techniques with UV and ICP-MS detection. Journal of Analytical Atomic Spectrometry 20, 176–182.
| Iodine speciation studies in commercially available seaweed by coupling different chromatographic techniques with UV and ICP-MS detection.Crossref | GoogleScholarGoogle Scholar |
Sorrenti S, Baldini E, Pironi D, Lauro A, D’Orazi V, Tartaglia F, Tripodi D, Lori E, Gagliardi F, Praticò M, Illuminati G, D’Andrea V, Palumbo P, Ulisse S (2021). Iodine: Its Role in Thyroid Hormone Biosynthesis and Beyond. Nutrients 13, 4469
| Iodine: Its Role in Thyroid Hormone Biosynthesis and Beyond.Crossref | GoogleScholarGoogle Scholar |
Vincent A, Stanley A, Ring J (2020) Hidden champion of the ocean: Seaweed as a growth engine for a sustainable European future, Seaweed for Europe, 2020. Available at https://www.seaweedeurope.com/wp-content/uploads/2020/10/Seaweed_for_Europe-Hidden_Champion_of_the_ocean-Report.pdf
Zimmermann MB, Boelaert K (2015). Iodine deficiency and thyroid disorders. The Lancet Diabetes & Endocrinology 3, 286–295.
| Iodine deficiency and thyroid disorders.Crossref | GoogleScholarGoogle Scholar |
