https://orbit.dtu.dk/files/4023711/ACA-Review-129I-speciation-finalversion.pdf

A review on speciation of iodine-129 in the environmental and biological samples

Latest studies on the chemical association of trace elements to large biomolecules and their importance on the bioinorganic and clinical fields are examined. The complexity of the speciation of metal-biomolecules associations in various biological fluids is stressed. Analytical strategies to tackle speciation analysis and the-state-of-the-art of the instrumentation employed for this purpose are critically reviewed. Hyphenated techniques based on coupling chromatographic separation techniques with ICP-MS detection are now established as the most realistic and potent analytical tools available for real-life speciation analysis. Therefore, the status and potential of metal and semimetals elemental speciation in large biocompounds using ICP-MS detection is mainly focused here by reviewing reported metallo-complexes separations using size-exclusion (SEC), ion-exchange (IE), reverse phase chromatography (RP) and capillary electrophoresis (CE). Species of interest include coordination complexes of metals with larger proteins (e.g. in serum, breat milk, etc.) and metallothioneins (e.g. in cytosols from animals and plants) as well as selenoproteins (e.g. in nutritional supplements), DNA-cisplatin adducts and metal/semimetal binding to carbohydrates. An effort is made to assess the potential of present trace elements speciation knowledge and techniques for "heteroatom-tagged" (via ICP-MS) proteomics.

Trace element speciation by ICP-MS in large biomolecules and its potential for proteomics.

Iodine dynamics in soils

Iodine is an essential trace element for humans and animals, and it is incorporated into the thyroid hormones such as thyroxine and triiodothyronine, which have multiple functions in energy metabolism and growth, but also as transmitter of nervous stimuli and as an important factor for brain development. Because of the small range between iodine requirements and the upper level for humans (between 1:2.5 and 3), the requirements should be met, but excesses should be avoided. One of the most important iodine sources for humans is milk of ruminants. Therefore, various influencing factors on the iodine content of milk of ruminants should be analyzed in the paper.
 The iodine content of milk depends on many factors, such as iodine content and level of iodine supplementation of feed, iodine source, iodine antagonists such as glucosinolates in the feed, farm management, teat dipping with iodine-containing substances, and milk processing in the dairy. The effects of some factors on the iodine content of milk are demonstrated and discussed. Feed iodine supplementation has the main effect on milk iodine. However, the iodine content of milk may vary considerably depending on many other influencing factors. As a consequence of preventive consumer protection, the European Food Safety Authority proposed a reduction in the iodine upper level for lactating ruminants from 5 to 2 mg/kg complete feed.

Influencing factors on iodine content of cow milk

Review of analytical methods for the quantification of iodine in complex matrices.

A combination of ion chromatography (IC) and inductively coupled plasma-mass spectrometry (ICP-MS) was used to determine iodine species in Thuringian milk samples. The developed method allows the fast and sensitive determination of iodine species with limits of determination for iodide and iodate <2 µg/L. Iodide was identified as the main iodine species in milk, but in a few samples also traces of iodate and several unidentified, presumably organoiodine compounds were observed as well. In addition, the total iodine concentration in the samples was determined by ICP-MS and gives an idea about the actual iodine state in Thuringian milk.

M. Leiterer

Papers

Determination of iodine species in milk using ion chromatographic separation and ICP-MS detection