Iodine status of Turkish pregnant women and their offspring: A national cross-sectional survey.

BACKGROUND: This national cross-sectional survey aimed to assess the iodine status in pregnant women and their offspring, and also to demonstrate regional differences by measuring urinary iodine concentration (UIC). For each woman and her newborn a questionnaire was prepared with basic facts as age, parity number or birth weight and additional information regarding thyroid diseases, use of iodized salt in the household, extra iodine supplementation during pregnancy, education level and wage income. METHODS: The target population represented 1444 pregnant women who gave birth between January 1 st, 2018 and 2019, and their offspring. Iodine deficiency for pregnant women and their offspring were defined as urine iodine level <150 µg/L and <100 µg/L, respectively. Results are given as median (25th-75th percentile). RESULTS: The median UIC in the group of pregnant woman was 94 (52-153) µg/L. Within the sample of 1444 pregnant women, UIC indicative of mild iodine deficiency (100-149 µg/L) was present in 21 % (n = 306), moderate deficiency (50-99 µg/L) in 30 % (n = 430), and severe deficiency (<50 µg/L) in 23 % (n = 337). This study showed a prevalence of 74 % of iodine deficiency in Turkish pregnant woman. The median UIC in the group of offspring was 96 (41-191) µg/L. Within the new-borns, UIC indicative of mild iodine deficiency (50-99 µg/L) was present in 22 % (n = 323), moderate deficiency (20-49 µg/L) in 15 % (n = 222), and severe deficiency (<20 µg/L) in 13 % (n = 192). This survey showed a prevalence of 51 % of iodine deficiency in Turkish new-borns. Pregnant women with lower socioeconomic and education level, lower access to household iodized salt, lower rates of exposure to povidone-iodine containing skin disinfectant, higher parity and higher iodine deficiency had higher rates of iodine deficiency in their offspring. Regional differences were observed both in mothers and their offspring concerning their iodine status. CONCLUSIONS: Our findings suggest that iodine deficiency is still an important public health problem in Turkey. More drastic measures should be taken to decrease these important iodine deficiencies, both in pregnant women and in their offspring.

Obesity and Monitoring Iodine Nutritional Status in Schoolchildren: is Body Mass Index a Factor to Consider?

Background: The frequency of overweight (OW) and obese (OB) children has increased worldwide, particularly in economically developed countries. No studies have been conducted to verify whether the increasing frequency of OW and obesity in schoolchildren may affect the evaluation of iodine nutritional status in populations. The aim of this study was to verify whether urinary iodine concentration (UIC), thyroid volume (TV), and thyroid hypoechoic pattern may be affected by body mass index (BMI) in schoolchildren. Methods: The children included in this study (aged 11-13 years) were a part of the schoolchildren recruited in the second nationwide survey (period 2015-2019) conducted in Italy to monitor by law (Atto di Intesa Stato-Regioni February 26, 2009) the nationwide iodine prophylaxis program. Specifically, 1281 schoolchildren residing in iodine-sufficient areas (IS group) and 384 children residing in a still mildly iodine-deficient area (ID group) were recruited between January and March 2015 in the first-degree secondary state schools. In all the children, spot UIC was measured, thyroid ultrasound was performed to evaluate TV, and hypoechogenicity was assessed to indirectly evaluate iodine-associated thyroid autoimmunity. Results: The frequency of OW, OB, and adequate weight (AW) children was similar in the IS and ID groups at any age. After adjusting for sex and age, the regression analysis showed lower UIC values in OB children than in AW children of the IS group (beta coefficient = -34.09 [95% confidence interval -65.3 to -2.8]), whereas no significant differences were observed in the ID group. In both the IS and ID groups, the distribution of TV in AW children was significantly shifted toward lower values in comparison to the distribution of OB children (p < 0.001 in the IS group; p = 0.012 in the ID group). Furthermore, the frequency of thyroid hypoechogenicity was higher in the ID group than in the IS group (10.9% vs. 6.6%, p = 0.005); however, in both groups, it was significantly lower in AW children than in OB children (p < 0.01). Conclusions: This study for the first time demonstrates that BMI may be a confounding factor in monitoring iodine nutritional status in schoolchildren. Since in Italy as in other Western countries the number of OW and OB children is high, BMI is a factor to consider in monitoring salt iodization programs worldwide.

Electrochemical sensor for the quantification of iodide in urine of pregnant women.

An electrochemical method has been developed to determine iodide in urine using an electrode modified with silver oxide microparticles-poly acrylic acid/poly vinyl alcohol (Ag2OMPs-PAA/PVA). Silver oxide particles were formed by electrochemical oxidation via cyclic voltammetry. The modified electrode exhibited an excellent response to iodide detection by cathodic stripping voltammetry. The fabrication and operation conditions were optimized in terms of PVA concentration, K2HPO4 concentration, amount of AgMPs-PAA/PVA, number of cycles for oxide formation, electrolyte, applied potential (vs. Ag/AgCl), and time. Under the optimum conditions, iodide determination produced a linear range from 1 to 40 µM. The limit of detection was 0.3 µM. Precision was found to be within 7.4% RSD. The developed method was applied to the determination of iodide in urine samples of pregnant women with satisfying recoveries (86 ± 1 to 108 ± 1%). Graphical abstract.

Shift of Reference Values for Thyroid Volume by Ultrasound in 8- to 13-Year-Olds with Sufficient Iodine Intake in China.

BACKGROUND: The iodine nutritional status of the Chinese population has been greatly improved in recent years. Therefore, the reference values for thyroid volume (Tvol) in children with sufficient iodine intake need to be updated. The study aimed to update the reference values for Tvol in children with sufficient iodine intake in order to define goiter in the context of sustained iodine sufficiency. METHODS: A cross-sectional study was conducted in children with sufficient iodine intake in China. Twice-repeated 24-hour urine samples were collected from each child to estimate habitual daily iodine intake. Serum thyroid function tests were measured. Tvol was assessed by ultrasound. From the sample of euthyroid children with sufficient iodine intakes, the 50th and 97th percentiles for Tvol by age and body surface area (BSA) were calculated using quantile regression. RESULTS: A total of 679 children aged 8-13 years with sufficient iodine intake (188 µg/day [145-235 µg/day]) were included in the analysis. The mean Tvol of the children was 4.1 ± 1.6 mL, and no differences were found between boys and girls in any age or BSA group. Quantile regression models demonstrated that BSA was a strong positive predictor of Tvol (p < 0.0001), while age only had a significant effect on median Tvol (p = 0.013). Sex was not a significant predictor of Tvol in children. CONCLUSIONS: The reference values for Tvol in Chinese children have been updated. This study indicates that the upper limit of (97th percentile) Tvol was dependent on BSA, while the median Tvol was determined by both age and BSA.

[Assessment of iodine nutritional status for pregnant women using adjusted urine creatinine from spot and 24-hour urine].

OBJECTIVE: To establish a reliable method of iodine nutritional assessment for pregnant women using the adjusted urinary creatinine of spot urine and 24-hour urine samples. METHODS: The spot urine in the morning at 8 00-11:30 and the following 24-hour urine samples of pregnant women were collected in Peking Union Medical College Hospital during March to October in 2016. The urinary iodine and urinary creatinine concentrations were determined. The estimated 24-hour urinary iodine excretion( 24-h UIE) was calculated using the urinary iodine/urinary creatinine( UIC/Cr) ratio of spot urine, and 24-hour urinary creatinine excretion( 24-h UCr E). RESULTS: There was a significant difference in the UIC, UIC/Cr ratio between spot urine and 24-h urine( P <0. 05). The UIC, UIC/Cr ratio of spot urine, and the estimated 24-h UIE all were significantly correlated with the real 24-h UIE( P < 0. 01), especially the estimated 24-h UIE were taking up 70%-80% for the real 24-h UIE in the period of gestation. CONCLUSION: The UIC, UIC/Cr, and the estimated 24-h UIE cannot directly replace the relevant values derived of the 24-hour urine samples. But the estimated 24-h UIE can reflect the iodine nutritional status of pregnant women in recent days, and the method could be a reliable reference for the iodine nutritional assessment of the pregnant women in practice.

Effect of Iodine Nutrition on Pregnancy Outcomes in an Iodine-Sufficient Area in China.

Many studies focused on the association between thyroid disease and pregnancy outcomes. The present study explored the effect of iodine nutrition during the first trimester on pregnancy outcomes. One thousand five hundred sixty-nine pregnant, euthyroid women at ≤12 weeks of gestation in an iodine-sufficient area in China were recruited. According to the World Health Organization (WHO) criteria for iodine nutrition during pregnancy, participants were divided into four groups: adequate iodine (median urinary iodine concentration (UIC), 150-249 µg/L), mild deficiency (UIC, 100-150 µg/L), moderate and severe deficiency (UIC, <100 µg/L), and more than adequate and excessive (UIC, ≥250 µg/L) groups. Pregnancy outcomes, including abortion, gestational hypertension, pre-eclampsia, gestational diabetes mellitus (GDM), placenta previa, placental abruption, preterm labor, low birth weight infants, macrosomia, breech presentation, and cord entanglement, were obtained during follow-up. The results showed that there was no significant difference in general characteristics, including age, body mass index, abdominal circumference, systolic blood pressure, diastolic blood pressure, heart rate, smoking rate, and drinking rate, among the four groups. In the more than adequate and excessive group, thyroid-stimulating hormone (TSH) was greater and free thyroxine (FT4) was lower than any other groups but still within normal range. The thyroglobulin (Tg) level was greater in the moderate and severe deficiency group. The incidence of GDM was significantly greater in women with mild iodine deficiency than in women with adequate iodine nutriture (18.38 vs. 13.70%, p < 0.05). Compared with the adequate group, incidence of macrosomia was significantly greater in the more than adequate and excessive group (12.42 vs. 9.79%, p < 0.05). Mild iodine deficiency was an independent risk factor for GDM (odds ratio = 1.566, 95% confidence interval = 1.060-2.313, p = 0.024); more than adequate and excessive iodine was an independent risk factor for macrosomia (OR = 1.917, CI = 1.128-3.256, p = 0.016). In summary, during 1st trimester, both mild iodine deficiency and excessive iodine intake had adverse impacts on pregnancy outcomes in an iodine-sufficient area.

In vivo uptake of iodine from a Fucus serratus Linnaeus seaweed bath: does volatile iodine contribute?

Seaweed baths containing Fucus serratus Linnaeus are a rich source of iodine which has the potential to increase the urinary iodide concentration (UIC) of the bather. In this study, the range of total iodine concentration in seawater (22-105 µg L-1) and seaweed baths (808-13,734 µg L-1) was measured over 1 year. The seasonal trend shows minimum levels in summer (May-July) and maximum in winter (November-January). The bathwater pH was found to be acidic, average pH 5.9 ± 0.3. An in vivo study with 30 volunteers was undertaken to measure the UIC of 15 bathers immersed in the bath and 15 non-bathers sitting adjacent to the bath. Their UIC was analysed pre- and post-seaweed bath and corrected for creatinine concentration. The corrected UIC of the population shows an increase following the seaweed bath from a pre-treatment median of 76 µg L-1 to a post-treatment median of 95 µg L-1. The pre-treatment UIC for both groups did not indicate significant difference (p = 0.479); however, the post-treatment UIC for both did (p = 0.015) where the median bather test UIC was 86 µg L-1 and the non-bather UIC test was 105 µg L-1. Results indicate the bath has the potential to increase the UIC by a significant amount and that inhalation of volatile iodine is a more significant contributor to UIC than previously documented.

Silver nanoclusters with enhanced fluorescence and specific ion recognition capability triggered by alcohol solvents: a highly selective fluorimetric strategy for detecting iodide ions in urine.

Alcohol solvents especially isopropanol were demonstrated for the first time to endow silver nanoclusters (AgNCs) in water with dramatically enhanced red fluorescence. More importantly, the specific iodide recognition capability of the AgNCs could thus be obtained towards a highly selective fluorimetric assay for detecting iodide ions in urine.

Reference Intervals of Thyroid Function During Pregnancy: Self-Sequential Longitudinal Study Versus Cross-Sectional Study.

BACKGROUND: A self-sequential longitudinal reference interval may be expected to minimize the inter-individual variation of thyroid function. Comparison between the self-sequential longitudinal reference interval (SLRI) and cross-sectional reference interval (CSRI) in pregnancy has not been well investigated. The objectives of this study were to establish a stringent SLRI of thyroid function in pregnant women and to compare it with the conventional CSRI. METHODS: Three cohorts were enrolled: group 1, pregnant women for an SLRI (n = 99); group 2, pregnant women for a CSRI (n = 1318); group 3, non-pregnant control women (NC) as a control group (n = 301) according to the criteria of the National Academy of Clinical Biochemistry. Thyrotropin (TSH), total thyroxine (TT4), free thyroxine (fT4), total triiodothyronine (TT3), free triiodothyronine (fT3), serum ferritin (SF), and urine iodine concentration (UIC) were measured in the three groups. RESULTS: Compared with CSRI, the reference interval of the SLRI group had narrower reference intervals of fT4 in the first and second trimesters (p < 0.05). The median of TSH was at a low level during the first trimester, and then gradually elevated in the second and third trimesters. The median of fT4 persistently decreased from 12 weeks, and did not return to the level of the NC group until 12 months postpartum. The TT4 increased to 131.4 nmol/L at gestational week 8, and reached a peak (170.0 nmol/L) at gestational week 12. In the first trimester, the prevalence of hypothyroxinemia was 9.1%, 4.0%, and 2.0% with a fT4 value below the 10th, 5th, and 2.5th percentile, respectively. In contrast, 29.3% of TT4 values were below the lower non-pregnancy reference limit multiplied by 1.5. CONCLUSIONS: No significant difference was found between a SLRI and a CSRI, even in a stringent self-sequential longitudinal reference interval of thyroid function in pregnant women. In addition, the limit of TT4 below the non-pregnant level multiplied by a factor 1.5 is not appropriate for diagnosing hypothyroxinemia in the first trimester.

Dietary Iodine Sufficiency and Moderate Insufficiency in the Lactating Mother and Nursing Infant: A Computational Perspective.

The Institute of Medicine recommends that lactating women ingest 290 µg iodide/d and a nursing infant, less than two years of age, 110 µg/d. The World Health Organization, United Nations Children's Fund, and International Council for the Control of Iodine Deficiency Disorders recommend population maternal and infant urinary iodide concentrations ≥ 100 µg/L to ensure iodide sufficiency. For breast milk, researchers have proposed an iodide concentration range of 150-180 µg/L indicates iodide sufficiency for the mother and infant, however no national or international guidelines exist for breast milk iodine concentration. For the first time, a lactating woman and nursing infant biologically based model, from delivery to 90 days postpartum, was constructed to predict maternal and infant urinary iodide concentration, breast milk iodide concentration, the amount of iodide transferred in breast milk to the nursing infant each day and maternal and infant serum thyroid hormone kinetics. The maternal and infant models each consisted of three sub-models, iodide, thyroxine (T4), and triiodothyronine (T3). Using our model to simulate a maternal intake of 290 µg iodide/d, the average daily amount of iodide ingested by the nursing infant, after 4 days of life, gradually increased from 50 to 101 µg/day over 90 days postpartum. The predicted average lactating mother and infant urinary iodide concentrations were both in excess of 100 µg/L and the predicted average breast milk iodide concentration, 157 µg/L. The predicted serum thyroid hormones (T4, free T4 (fT4), and T3) in both the nursing infant and lactating mother were indicative of euthyroidism. The model was calibrated using serum thyroid hormone concentrations for lactating women from the United States and was successful in predicting serum T4 and fT4 levels (within a factor of two) for lactating women in other countries. T3 levels were adequately predicted. Infant serum thyroid hormone levels were adequately predicted for most data. For moderate iodide deficient conditions, where dietary iodide intake may range from 50 to 150 µg/d for the lactating mother, the model satisfactorily described the iodide measurements, although with some variation, in urine and breast milk. Predictions of serum thyroid hormones in moderately iodide deficient lactating women (50 µg/d) and nursing infants did not closely agree with mean reported serum thyroid hormone levels, however, predictions were usually within a factor of two. Excellent agreement between prediction and observation was obtained for a recent moderate iodide deficiency study in lactating women. Measurements included iodide levels in urine of infant and mother, iodide in breast milk, and serum thyroid hormone levels in infant and mother. A maternal iodide intake of 50 µg/d resulted in a predicted 29-32% reduction in serum T4 and fT4 in nursing infants, however the reduced serum levels of T4 and fT4 were within most of the published reference intervals for infant. This biologically based model is an important first step at integrating the rapid changes that occur in the thyroid system of the nursing newborn in order to predict adverse outcomes from exposure to thyroid acting chemicals, drugs, radioactive materials or iodine deficiency.

Simple, Robust, and Plasticizer-Free Iodide-Selective Sensor Based on Copolymerized Triazole-Based Ionic Liquid.

Novel solid-contact iodide-selective electrodes based on covalently attached 1,2,3 triazole ionic liquid (IL) were prepared and investigated in this study. Triazole-based IL moieties were synthesized using click chemistry and were further copolymerized with lauryl methacrylate via a simple one-step free radical polymerization to produce a "self-plasticized" copolymer. The mechanical properties of the copolymer are suitable for the fabrication of plasticizer-free ion-selective membrane electrodes. We demonstrate that covalently attached IL moieties provide adequate functionality to the ion-selective membrane, thus achieving a very simple, one-component sensing membrane. We also demonstrate that the presence of iodide as the counterion in the triazole moiety has direct influence on the membrane's functionality. Potentiometric experiments revealed that each electrode displays high selectivity toward iodide anions over a number of inorganic anions. Moreover, the inherent presence of the iodide in the membrane reduces the need for conditioning. The nonconditioned electrodes show strikingly similar response characteristics compared to the conditioned ones. The electrodes exhibited a near Nernstian behavior with a slope of -56.1 mV per decade across a large concentration range with lower detection limits found at approximately 6.3 × 10(-8) M or 8 ppb. These all-solid-state sensors were utilized for the selective potentiometric determination of iodide ions in artificial urine samples in the nanomolar concentration range.

[Repeated cross-sectional studies on urinary iodine and iodine content of salt among school-aged children from 2012 to 2014 in Yuhuan County, Zhejiang Province].

OBJECTIVE: To investigate the iodine status and its change among school-aged children in their morning urine and eating salt from 2012 to 2014 in Yuhuan County, Zhejiang Province, China. METHODS: Three repeated cross-sectional studies were carried out at a same primary school in 2012, 2013 and 2014, respectively. Three classes were randomly selected from each of 3 to 5 grade by the cluster-stratified sampling every year. Totally, 1343 out of 1350 eligible children aged 8 to 10 years old were involved into this study. Their morning urine and salt eating at home were collected and tested. RESULTS: The overall median of urine iodine was 116.0 µg/L, and no significant change was found over year. The overall proportions of subjects with urine iodine < 50 µg/L, < 100 µg/L, and ≥ 300 µg/L were 4.8%, 38.6% and 3.5%, respectively, and there were little differences over year, gender and grade of children. An overall median of iodine from 1343 salt samples was 0.0 mg/kg and no year difference was statistically observed. The proportions of subjects consumed iodized salt significantly decreased from 25.1% in 2012 to 21.8% in 2013 and to 14.2% in 2014. There was a significant difference in urine iodine between subjects taken iodized salt or not and also a weak positive correlation between salt iodine and urine iodine. CONCLUSION: The nutritional status of iodine is overall stable, proper and safety in recent 3 years among school children in Yuhuan County. The coverage rate of iodized salt is very low.

Ratiometric fluorophore for quantification of iodide under physiological conditions: applications in urine analysis and live cell imaging.

Dipod 1 bearing two pyrenyl tethered benzimidazolium moieties gives a fluorescence spectrum in aqueous medium which reveals a structured emission band between 330-400 nm and a broad emission band centered at 475 nm, respectively due to monomer and excimer emission of the pyrene moieties. The presence of an excimer emission band points to the formation of a pseudocyclic structure. Dipod 1 undergoes highly selective fluorescence quenching of the excimer emission band in the presence of iodide ions, whereas the fluorescence intensity of the monomer emission band remains stable. The ratio of fluorescence intensity I395 nm/I475 nmvs. log [I(-)] undergoes a linear change over a broad iodide concentration range of 10(-9) to 10(-5) M with KSV 3.7 × 10(5) M(-1). Dipod 1 can be used to determine iodide ions in urine samples, tap water and sea water conditions with 1 nM iodide as the lowest detection limit. On using paper strips coated with dipod 1, ∼1.7 pg cm(-2) iodide ions could be detected. Dipod 1 shows a fluorescence quenching response to 100 nM iodide ions in C6 glioma cells using confocal microscopy. The life time of the dipod 1 shows a linear decrease with log [I(-)] and points to coordination based recognition of iodide ion.

"Molecular beacon"-hosted thioflavin T: Applications for label-free fluorescent detection of iodide and logic operations.

In this work, we presented a simple, label-free and rapid-responsive fluorescence assay for iodide (I(-)) detection based on "molecular beacon (MB)"-hosted thioflavin T (ThT), achieving a limit of detection as low as 158 nM. The proposed method exhibited very good selectivity to I(-) ions over other anions interference due to the strong binding force between I(-) ions with Hg(2+). Upon the addition of I(-) ions, it would capture Hg(2+) from a T-Hg(2+)-T complex belonging to the MB-like DNA hairpin structure, which eventually quenched the initial fluorescence as output. In addition, it was successfully applied for operation of an integrated DNA logic gate system and to the determination of I(-) in real samples such as human urine.

A probe with aggregation induced emission characteristics for screening of iodide.

The dilution controlled aggregation enhanced emission of spherically aggregated form of a triazole based probe dies down upon detecting iodide over other inorganic anions. The sensing is realised as a dynamic quenching mechanism dominated event. Being highly selective for iodide, the probe finds application in the detection of iodide in human urine.

Metallothionein-I/II Knockout Mice Aggravate Mitochondrial Superoxide Production and Peroxiredoxin 3 Expression in Thyroid after Excessive Iodide Exposure.

PURPOSE: We aim to figure out the effect of metallothioneins on iodide excess induced oxidative stress in the thyroid. METHODS: Eight-week-old MT-I/II knockout (MT-I/II KO) mice and background-matched wild-type (WT) mice were used. Mitochondrial superoxide production and peroxiredoxin (Prx) 3 expression were measured. RESULTS: In in vitro study, more significant increases in mitochondrial superoxide production and Prx 3 expression were detected in the MT-I/II KO groups. In in vivo study, significantly higher concentrations of urinary iodine level were detected in MT-I/II KO mice in 100 HI group. Compared to the NI group, there was no significant difference existing in serum thyroid hormones level in either groups (P > 0.05), while the mitochondrial superoxide production was significantly increased in 100 HI groups with significantly increased LDH activity and decreased relative cell viability. Compared to WT mice, more significant changes were detected in MT-I/II KO mice in 100 HI groups. No significant differences were detected between the NI group and 10 HI group in both the MT-I/II KO and WT mice groups (P > 0.05). CONCLUSIONS: Iodide excess in a thyroid without MT I/II protection may result in strong mitochondrial oxidative stress, which further leads to the damage of thyrocytes.

Effect of a Low Iodine Diet vs. Restricted Iodine Diet on Postsurgical Preparation for Radioiodine Ablation Therapy in Thyroid Carcinoma Patients.

PURPOSE: The radioiodine ablation therapy is required for patients who underwent a total thyroidectomy. Through a comparative review of a low iodine diet (LID) and a restricted iodine diet (RID), the study aims to suggest guidelines that are suitable for the conditions of Korea. MATERIALS AND METHODS: The study was conducted with 101 patients. With 24-hour urine samples from the patients after a 2-week restricted diet and after a 4-week restricted diet, the amount of iodine in the urine was estimated. The consumed radioiodine amounts for 2 hours and 24 hours were calculated. RESULTS: This study was conducted with 47 LID patients and 54 RID patients. The amounts of iodine in urine, the 2-week case and 4-week case for each group showed no significant differences. The amounts of iodine in urine between the two groups were both included in the range of the criteria for radioiodine ablation therapy. Also, 2 hours and 24 hours radioiodine consumption measured after 4-week restrictive diet did not show statistical differences between two groups. CONCLUSION: A 2-week RID can be considered as a type of radioiodine ablation therapy after patients undergo a total thyroidectomy.

Fluorescent organic nanoparticles of dihydropyrimidone derivatives for selective recognition of iodide using a displacement assay: application of the sensors in water and biological fluids.

Fluorescent organic nanoparticles (FON's) derived from dihydropyrimidone derivatives (1-4) were developed and evaluated for their sensor properties. Nano-aggregates of compound 3 and 4 resulted in sensors. Nano-aggregates of compound 3 showed enhancement in the monomer peaks of the pyrene moiety after the addition of mercury. Nano-aggregates of compound 4 resulted in quenching of intensity upon addition of Hg(2+). On the other hand, no sensor activity was recorded for nano-aggregates of compounds 1 and 2. Further, the complex of nano-aggregates of 3 and mercury (3·Hg(2+)) recognised iodide ions by showing quenching in monomer and excimer emission with a detection limit of 0.2 nM in aqueous medium; however the resultant metal complex 4·Hg(2+) does not show any anion sensing activity. Receptor 3·Hg(2+) has a highly sensitive and selective response toward I(-) ions. Therefore, the iodide content of tap water, urine and blood serum is monitored using this sensor and it is found that the sensor can detect a range of iodide in tap water, urine and blood serum. To the best of our knowledge, the system represents the first example of iodide recognition using FONs.

Simultaneous determination of iodide and creatinine in human urine by flow analysis with an on-line sample treatment column.

This work presents the first flow system for direct analysis of iodide and creatinine suitable for screening of human urine samples. The system had a mini-column packed with strong anion exchange resin for on-line extraction of iodide. After injection of a sample on the column the unretained urine sample was analyzed for creatinine in one section of the flow system using the Jaffe's reaction with spectrometric detection at 520 nm. Iodide was eluted off with 1.42 mL 5 M NaNO3. A 150 µL fraction of the eluate was analyzed in another section of the same flow system for iodide using the kinetic-spectrometric Sandell-Kolthoff reaction. At the optimum condition, the sample throughput was 12 samples per h. The linear working range covered the normal levels of iodide and creatinine in human urine: 0-200 µg I L(-1) and 50-1200 mg creatinine L(-1), respectively. Recoveries tested in 10 samples were 87-104% for iodide and 89-104% for creatinine. Bland-Altman plots (n = 50) showed that the scatter of the differences between values obtained by this method and those of reference methods, for both iodide and creatinine, was within mean ± 2SD.

Characterization of a rapid and reliable method for iodide biomonitoring in serum and urine based on ion chromatography-ICP-mass spectrometry.

An appropriate and controlled supply of thyroid hormones is vital for proper body function. In turn, an appropriate synthesis of T3 and T4 in the thyroid gland is dependent on a sufficient and balanced iodide concentration in blood serum. Due to widespread iodine deficiency or some cases of iodine over exposure, iodide biomonitoring in serum is important and it is that biomonitoring approach being closest to the bioavailable I(-) supply for the thyroid gland. Therefore, this paper describes a biomonitoring method for iodide determination in serum based on ion chromatography-inductively coupled plasma mass spectrometry (IC-ICP-MS). Since in literature only very few data are available on iodide in serum but many in urine the method is also extended to I(-) monitoring in urine. The method was additionally designed to have short analysis time (8min) for increased sample throughput, good precision in serial measurement (serum: 4.86%; urine: 1.4%), and day-to-day determination (serum: 5.7%; urine: 2.28%), high accuracy (serum: 105%; urine: 101%) and good recovery (serum: 102%; urine: 99%) even in matrix-rich samples at low I(-) concentration. Also, investigations were performed to elucidate whether internal standardization during chromatography, sample preparation for protein-matrix removal or matrix-matched calibration are advantageous for analytical performance. Finally, limits of detection (3σ) of 0.12µg/L or 0.05µg/L (serum or urine) and limit of quantification (10σ) of 0.39µg/L or 0.17µg/L (serum or urine) were achieved.