A high accuracy primary ratio method for the determination of iodine in complex matrices by double isotope dilution using MC-ICPMS and 129I spike

Santamaría-Fernández, Rebeca; Evans, Peter; Wolff-Briche, C.; Hearn, Ruth

doi:10.1039/b516767a

Cited by 23 publications

(33 citation statements)

References 22 publications

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“…An aliquot of 0·5 g was mixed with 5 ml of 5 % tetramethylammonium hydroxide (TMAH) solution, prepared by dissolving solid TMAH ( ≥ 97 %; Sigma Aldrich, Gillingham, Dorset, UK) in ultrapure water. The vial was then placed in an oven at 90°C for 3 h ( 23 ) . To each sample, 0·5 ml of the internal standard was added (1300 ng/ml tellurium in 1 % TMAH; Romil, Cambridge, UK) and the samples were made up to 50 g with 1 % TMAHsolution.…”

Section: Methodsmentioning

confidence: 99%

Iodine concentration of organic and conventional milk: implications for iodine intake

2011

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Iodine is required for adequate thyroid hormone production, which is essential for brain development, particularly in the first trimester of pregnancy. Milk is the principal source of iodine in UK diets, and while small studies in Europe have shown organic milk to have a lower iodine concentration than conventional milk, no such study has been conducted in Britain. In view of the increasing popularity of organic milk in the UK, we aimed to compare the iodine concentration of retail organic and conventional milk and to evaluate regional influences in iodine levels. Samples of organic milk (n 92) and conventional milk (n 80), purchased from retail outlets in sixteen areas of the UK (southern England, Wales and Northern Ireland), were analysed for iodine using inductively coupled plasma MS. The region of origin of the milk was determined from information on the label. Organic milk was 42·1 % lower in iodine content than conventional milk (median iodine concentration 144·5 v. 249·5 ng/g; P,0·001). There was no difference in the iodine concentration of either conventional or organic milk by area of purchase. However, a difference was seen in iodine concentration of organic milk by region of origin (P, 0·001). The lower iodine concentration of organic milk has public-health implications, particularly in view of emerging evidence of iodine deficiency in UK population sub-groups, including pregnant women. Individuals who choose organic milk should be aware that their iodine intake may be compromised and should ensure adequate iodine intake from alternative sources.Key words: Iodine: Organic produce: Milk: United Kingdom Iodine is needed for the production of thyroid hormones that are vital during pregnancy and infancy owing to their role in brain and neurological development (1) . While severe iodine deficiency can cause gross mental deficiency and infant mortality (1) , there is emerging evidence that mild-to-moderate maternal iodine deficiency is associated with impaired infant development, including lower intelligence quotient (IQ) and increased incidence of attention deficit hyperactivity disorder (2) . For these reasons, pregnant women are vulnerable to iodine deficiency (1) . The iodine content of foods is dependent on the source of the food, whether from sea or land, the soil content (affected by geology, geography, pH and soil leaching) and farming practice (1) . In the UK, milk and dairy products are the most important sources of dietary iodine, contributing as much as 42 % of adult intake (3) . Higher milk-iodine concentration and increased milk consumption have been cited as the reasons for the eradication of endemic goitre in the UK in the 1960s, which was labelled as an 'accidental public health triumph' by Phillips (4) . Iodine sufficiency has been assumed in the UK for many years (5,6) and iodised salt is scarcely available (7) .However, there is emerging concern that the iodine status of the population, particularly of young women (8 -10) and pregnant women (7) , may be inadequate. Although conv...

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Section: Methodsmentioning

confidence: 99%

Iodine concentration of organic and conventional milk: implications for iodine intake

2011

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“…Sample preparation and analysis were performed using a method previously validated in-house against a primary reference method, namely isotope dilution mass spectrometry(28). In brief, the samples were first digested by mixing 0.5 g liquid (weighed to four decimal places) in a glass vial with 5 ml of 5% tetramethylammonium hydroxide (TMAH), prepared using solid TMAH (≥97%; Sigma Aldrich, Gillingham, Dorset, UK) dissolved in ultrapure water (18.2 MΩ cm, Elga PureFlex, UK).…”

Section: Methodsmentioning

confidence: 99%

Iodine concentration of milk-alternative drinks available in the UK in comparison with cows’ milk

Bath

Hill²,

Infante³

et al. 2017

Br J Nutr

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Iodine deficiency is present in certain groups of the UK population, notably in pregnant women; this is of concern as iodine is required for fetal brain development. UK milk is rich in iodine and is the principal dietary iodine source. UK sales of milk-alternative drinks are increasing but data are lacking on their iodine content. As consumers may replace iodine-rich milk with milk-alternative drinks, we aimed to measure the iodine concentration of those available in the UK. Using inductively coupled plasma-MS, we determined the iodine concentration of seven types of milk-alternative drink (soya, almond, coconut, oat, rice, hazelnut and hemp) by analysing forty-seven products purchased in November/December 2015. For comparison, winter samples of conventional (n 5) and organic (n 5) cows' milk were included. The median iodine concentration of all of the unfortified milk-alternative drinks (n 44) was low, at 7·3 μg/kg, just 1·7 % of our value for winter conventional cows' milk (median 438 μg/kg). One brand (not the market leader), fortified its soya, oat and rice drinks with iodine and those drinks had a higher iodine concentration than unfortified drinks, at 280, 287 and 266 μg/kg, respectively. The iodine concentration of organic milk (median 324 μg/kg) was lower than that of conventional milk. Although many milk-alternative drinks are fortified with Ca, at the time of this study, just three of forty-seven drinks were fortified with iodine. Individuals who consume milk-alternative drinks that are not fortified with iodine in place of cows' milk may be at risk of iodine deficiency unless they consume alternative dietary iodine sources.

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“…The most common of the traditional methods is colorimetry based on the Sandell-Kolthoff reaction, in which iodide catalyzes the reduction of ceric ammonium sulfate by arsenious acid (15)(16)(17)(18). The emergence of newer instrumental methods based on coupled ion chromatography and inductively coupled plasma mass spectrometry (ICP-MS) permit measurements of greater specificity and sensitivity, although at higher cost (19)(20)(21)(22).…”

Section: Srms For Urinary Iodinementioning

confidence: 99%

Development of Standard Reference Materials to support assessment of iodine status for nutritional and public health purposes

Long

Catron

Boggs

et al. 2016

The American Journal of Clinical Nutrition

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The use of urinary iodine as an indicator of iodine status relies in part on the accuracy of the analytical measurement of iodine in urine. Likewise, the use of dietary iodine intake as an indicator of iodine status relies in part on the accuracy of the analytical measurement of iodine in dietary sources, including foods and dietary supplements. Similarly, the use of specific serum biomarkers of thyroid function to screen for both iodine deficiency and iodine excess relies in part on the accuracy of the analytical measurement of those biomarkers. The National Institute of Standards and Technology has been working with the NIH Office of Dietary Supplements for several years to develop higher-order reference measurement procedures and Standard Reference Materials to support the validation of new routine analytical methods for iodine in foods and dietary supplements, for urinary iodine, and for several serum biomarkers of thyroid function including thyroid-stimulating hormone, thyroglobulin, total and free thyroxine, and total and free triiodothyronine. These materials and methods have the potential to improve the assessment of iodine status and thyroid function in observational studies and clinical trials, thereby promoting public health efforts related to iodine nutrition.

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A high accuracy primary ratio method for the determination of iodine in complex matrices by double isotope dilution using MC-ICPMS and 129I spike

Cited by 23 publications

References 22 publications

Iodine concentration of organic and conventional milk: implications for iodine intake

Iodine concentration of organic and conventional milk: implications for iodine intake

Iodine concentration of milk-alternative drinks available in the UK in comparison with cows’ milk

Development of Standard Reference Materials to support assessment of iodine status for nutritional and public health purposes

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