Iodine in iodination

Regoeczi, E. (1984) Methods of protein iodination. In Iodine-labeled Plasma Proteins, Vol. 1, pp. 35-102. CRC Press, New York. 

Seaweeds food toxicants in [FOOD TOXICANTS, NATURALLY OCCURRING] (Volll) iodine in [IODINE AND IODINE COMPOUNDS] (Vol 14)... 

Delange et al. (Delange et al., 2002) determined the frequency distribution of urinary iodine in iodine-replete popnilations (schoolchildren and adults) and the proportion of concentrations <50 pg/1. The findings were as follows nineteen groups reported data from 48 popnilations with median urinary iodine concentrations >100 ig/l. The total population was 55 892, including 35 661 (64%) schoolchildren. Median urinary iodine concentrations were 111-540 (median 201) pg/1 for all populations, 100-199 ig/l in 23 (48%) populations and >/=200 jig/1 in 25 (52%). The frequencies of values <50 qg/1 were 0-20.8 (mean 4.8%) overall and 7.2% and 2.5% in populations with medians of 100-199 rg/l and >200 pg/1, respectively. The frequency reached 20% only in two places where iodine had been supplemented for <2 years. According to the authors conclusions the frequency of urinary iodine concentrations <50 Hg/1 in populations with median urinary iodine concentrations >/=100 rg/l has been overestimated, and the threshold of 100 qg/1 does not need to be increased. The main conclusion of the cited work was that in populations, median urinary iodine concentrations of 100-200 qg/1 indicate adequate iodine intake and optimal iodine nutrition. 

This is further indicated by evidence of the relation of maternal thyroxine levels to the risk of cretinism and the psychomotor defect from studies in Papua New Guinea (26). The subsequent lack of fetal thyroid hormones due to the inadequate supply of iodine in iodine deficiency would exacerbate the effects of maternal thyroid insufficiency and the combination of effects, which were represented experimentally in the sheep by maternal thyroidectomy before conception (21) combined with fetal thyroidectomy at 98 days (12), might be expected to produce the multiple defects of neurological cretinism. 

The second method uses preconcentration to increase the analyte concentration in the absorption solution to detectable levels prior to analysis. One example is the use of solid-phase extraction with an anion exchange column as a pretreatment technique to remove interference from the sample matrix and to enhance the detection sensitivity prior to determination of the concentrated iodide anion through reversed phase high-performance liquid chromatography (HPLC) using an ultraviolet (UV) detector. The results show more than 90% recovery and good reproducibility for the determination of trace iodine in iodine-enriched eggs. 

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