Iodate Species Research Articles

Selective elimination of sulfonamide antibiotics upon periodate/catechol process: Dominance of quinone intermediates

Natural organic matter, specifically ortho-quinones organics among them, was considered can participate in the transformation of sulfonamide antibiotics (SAs). Herein, based on targeted oxidizing for ortho-dihydroxyl structures (catechol as the model) upon periodate, an efficient approach for SAs elimination was introduced. Results first indicated the generation of ortho-benzoquinone (o-BQ) within periodate/catechol system progresses readily (the energy barriers for 9.6854 kcal/mol). The near-complete eliminations were observed towards sulfamethoxazole (SMX) in periodate/catechol system (with the rate of 0.4229 min−1) as well as other SAs and exhibited unprecedented resistance to operating parameters. Besides, periodate converts little into toxic low-valent iodate species during the reaction process, and both the cytotoxicity and acute toxicity assays revealed a significant decline in antibiotics bioactivity. Mechanistic insight revealed that o-BQ dominated the degradation process, comprehensive analysis further confirmed Michael addition reaction was the first degradation stage, in which electrons flow from o-BQ to SMX and form covalent bonds upon aniline. Furthermore, several catechol derivatives were used to verify the universality of the mechanism, and their wide distribution in both subsurface and wastewater implies the potential applications. Overall, the mechanisms elucidated behind this research proposed an efficient strategy for eliminating trace SAs in aqueous environments and selectively removing SAs from complex wastewater matrices.

Simultaneous determination of iodide and iodate in salty spices by liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS)

In this study, iodide and iodate species in food were simultaneously determined by LC-ICP-MS after sample treatment with Deion water based on ultrasonic extraction. The conditions of the instrument and the extraction procedure were investigated. The method was validated with calibration curves that have the coefficient of determination (R2) higher than 0.995. The method limits of detection (LOD) of iodide and iodate were 0.079 and 0.060 mg/kg respectively meeting the regulatory requirements for food safety management. The recoveries were in the range of 83.5 - 108% and the relative standard deviations (RSDr) were between 2.57 and 5.22%. These parameters met the requirements specified by AOAC. A total of 43 salty spice samples including table salts, iodized seasoning soup powders, seasoning seeds, oyster sauces, soy sauces, fish sauces were collected and analyzed for research purposes. The results showed that a high percentage (76.9%) of table salt and seasoning soup powder samples had total iodate and iodide content lower than the specified level. Meanwhile, other salty spice samples, especially seasoning seeds and soy sauces, had a significant content of iodide in the range of 2.0 to 13.2 mg/kg. This study has contributed to the preliminary assessment of the current status of iodine content in salty spice products collected in Hanoi city.

A Multi-Sensor System for Sea Water Iodide Monitoring and Seafood Quality Assurance: Proof-of-Concept Study.

Iodine is a trace chemical element fundamental for a healthy human organism. Iodine deficiency affects about 2 billion people worldwide causing from mild to severe neurological impairment, especially in children. Nevertheless, an adequate nutritional intake is considered the best approach to prevent such disorders. Iodine is present in seawater and seafood, and its common forms in the diet are iodide and iodate; most iodide in seawater is caused by the biological reduction of the thermodynamically stable iodate species. On this basis, a multisensor instrument which is able to perform a multidimensional assessment, evaluating iodide content in seawater and seafood (via an electrochemical sensor) and discriminating when the seafood is fresh or defrosted quality (via a Quartz Micro balance (QMB)-based volatile and gas sensor), is strategic for seafood quality assurance. Moreover, an electronic interface has been opportunely designed and simulated for a low-power portable release of the device, which should be able to identify seafood over or under an iodide threshold previously selected. The electrochemical sensor has been successfully calibrated in the range 10–640 μg/L, obtaining a root mean square error in cross validation (RMSECV) of only 1.6 μg/L. Fresh and defrosted samples of cod, sea bream and blue whiting fish have been correctly discriminated. This proof-of-concept work has demonstrated the feasibility of the proposed application which must be replicated in a real scenario.

Iodine local environment in high pressure borosilicate glasses: An X-ray photoelectron spectroscopy and X-ray absorption spectroscopy investigation

• Iodine is dissolved as iodide (I − ) in high pressure borosilicate glasses. • Both alkali and alkaline-earth cations act as a charge compensator to I − species. • The absence of iodate (I 5+ ) suggests that there is a complex interplay between I − species and oxygen species within the glass structure. The 129 I radioactive isotope is a by-product of nuclear plants activity. Owing to its strong volatility, there is currently no ideal protocol to immobilize 129 I in nuclear waste borosilicate glasses. Recently, we have proposed the use of high-pressure syntheses to dissolve iodine in various glass compositions; however, I speciation and dissolution mechanism could not be determined. We have adopted an approach combining X-ray Photoelectron Spectroscopy (XPS) and X-ray Absorption Spectroscopy (XAS) methods to determine I speciation and molecular environment in glasses containing from 0.5 to 2.5 mol.% I. The XPS spectra reveal that I is mostly dissolved as iodide (>85% I − ) with a small proportion of elemental iodine (<15% I 0 ) and the absence of iodate species (I 5+ ). For borosilicate glasses, the XAS results and subsequent spectrum simulations suggested that Na and Ca are involved in the I − vicinity with averaged derived coordination number (CN) of 3.6 and 2.0 and bond length to the nearest neighbour (r X-I ) 2.98 and 2.85 Å, respectively. These results suggest that the coexistence of both I − and I 5+ species is not requested for electric neutrality but instead, we explain the I speciation by the possible interplay with oxygen species from the borosilicate matrix. In addition, the results imply that the borosilicate network is affected by the I dissolution.

PERIODATE OXIDATION OF PEG–600, AN ESSENTIAL PHARMACEUTICAL POLYMER

Objective: To study the kinetics of periodate oxidation of polyethylene glycol-600 (PEG-600), a familiar non-toxic polymer used in pharmaceutical and other fields of industry.&#x0D; Methods: Reactions were carried out in alkaline medium and measured the kinetics by iodometry. One oxygen atom loss or two electrons transfer was observed per each molecule of periodate i.e., the rate of reaction was measured periodate converts to iodate because the formed iodate species is unable to oxidize the substrate molecules.&#x0D; Results: Based on log (a-x) versus t plots, order w. r. t. oxidant (periodate) is unity. Reactions were found to be independent of substrate (PEG-600) concentration. A decrease in rate with an increase in alkali concentration [OH–] was found and order was inverse fractional. Temperature dependence of reaction rate was studied and then calculated the corresponding Arrhenius parameters.&#x0D; Conclusion: An appropriate rate law was proposed by considering the above experimental results.

Tracing variability in the iodine isotopes and species along surface water transect from the North Sea to the Canary Islands

A complete transect of surface water samples from the North Sea to the Canary Islands was collected during a continuous period in 2010. The samples were analyzed for total 129I and 127I isotopes and their iodide and iodate species. The results indicate a large variability in the total 129I and its species along the transect, whereas less change and variation are observed for the total 127I and its species. Transport of 129I from the western English Channel via Biscay Bay is the main source of 129I in the northeastern Atlantic Ocean.

Size-resolved characterisation of organic compounds in atmospheric aerosols collected at Welgegund, South Africa

The organic fraction of atmospheric aerosols is 20 to 90 % of which only a small percentage has been chemically characterised. Two-dimensional gas chromatography with a time-of-flight mass spectrometer (GCxGC-TOFMS) is a powerful instrument used to chemically characterise organic compounds. Size-resolved characterisation and semi-quantification of ambient organic aerosol compounds were performed with a GCxGC-TOFMS for the first time in South Africa. Twenty-four-hour samples were collected for 1 year for three different size ranges. A combined total of 1056 different organic compounds could be tentatively characterised. The largest number of organic compounds tentatively identified was PM2.5–1 (particles in the size range 1–2.5 μm), while this size fraction also had the highest total number of normalised response factors (∑NRF). On average, 52, 26, 6, 13 and 3 % of species tentatively identified were oxygenated species, hydrocarbons, halogenated compounds, N-containing compounds and S-containing compounds, respectively. Oxygenated compounds were the most abundant species. Alkane and mono-aromatic species were the largest number of hydrocarbons tentatively identified with the highest ∑NRFs. The largest number of oxygenated species tentatively characterised were carboxylic acids and esters, while ether compounds had the highest ∑NRFs. Most of the halogenated compounds tentatively identified were chlorinated species with the highest ∑NRFs in two size fractions. Iodate species had a significantly higher ∑NRF in the PM2.5–1 size fraction. The largest number of N-containing species tentatively characterised with the highest ∑NRFs were amines. A small number of S-containing compounds with low ∑NRFs were tentatively identified. The major sources of organic compounds measured at Welgegund were considered to be biomass burning and air masses moving over the anthropogenically impacted source regions.

Geochemical controls of iodine uptake and transport in Savannah River Site subsurface sediments

Because iodine-129 has a half-life of nearly 16 million years, poses major health threats, and can be mobile in the environment, it is important to use the best estimates for kinetics of sorption in risk assessment models. Previous work estimating the iodine sorption has not allowed for samples to reach full equilibrium and field studies have reported significant fractions of up to three major species of iodine; therefore, further research into the kinetics of iodine sorption to sediments is warranted. The objective of this study is to investigate the kinetics of iodine sorption in the presence of subsurface upland sediments and wetland sediments from an area within an 129I plume at the Savannah River Site in Aiken, SC. Batch sorption studies for these systems took longer than 8weeks to reach equilibrium, which is significant as previous studies did not reach such timescales. In addition, experiments were conducted under oxic and anoxic conditions. Results confirm that there are three species present in these systems (iodide, iodate, and organo-iodine) with a majority as organo-iodine species at equilibrium for systems with high organic matter content. It is notable that the anoxic conditions exhibited reduced sorption for the iodate species to wetland sediment with high organic matter.

Chemical speciation analysis of 129I in seawater and a preliminary investigation to use it as a tracer for geochemical cycle study of stable iodine

Abstract A method was developed for the determination of the 129I and 127I in iodide and iodate species in seawater. Iodide and iodate were first separated by anion exchange method from seawater; the separated fractions of various chemical species of iodine were further concentrated by solvent extraction and then converted to LiI irradiation target. The concentrations of 129I and 127I in various fractions were determined by neutron activation analysis using nuclear reactions of 129I (n, γ)130I and 127I(n, γ) 128I, respectively. Surface and bottom seawater samples from three locations in the Kattegat and Baltic Sea were analyzed for 129I and 127I in both iodide and iodate species and total inorganic iodine. Levels as low as 2.3×10−15 M 129I and 7 nM 127I were measured. The possibility of using this method to study the geochemical cycle of iodine in the ocean was investigated. The preliminary results indicate that this is possible, and that this method can be also used for the investigation of the transport, dispersion and mixture of water masses by using 129I discharged from reprocessing facilities as a tracer.

Separation of iodine species by adsorption chromatography

Based on the different properties of iodide and iodate species in somesorption materials a new chromatographic method was developed to study thespeciation of iodine in a mangrove system. Two sorption materials, aluminaand silica, were investigated and several distribution coefficients for iodideand iodate were determined at different concentrations of NaOH, NaNO3 and NaHCO3 solutions. The best separation results wereobtained percolating sea water samples, containing iodine species, througha glass column filled with alumina. The iodide passed through the column afterwashing the column with 0.1M sodium nitrate solution, and the iodate was elutedwith a 0.5M sodium bicarbonate solution.

96/05528 Factors affecting interaction of radioiodide and iodate species with soil

96/05528 Factors affecting interaction of radioiodide and iodate species with soil

96/05525 Experimental study on properties of N2O and NOx emissions in a coal-fired fluidized bed

The uptake of radioiodide and iodate species by soil dried at 100 °C (particle size of less than 0.25 mm) was studied in laboratory batch experiments for three major groups of variables: (i) experimental conditions (ambient temperature, liquid-to-solid ratio and contact time), (ii) solid phase conditions (grain size and washing treatment), and (iii) liquid phase conditions (pH, and concentrations of electrolytes and carrier). Effects of the presence of soluble and insoluble organic matter were also investigated in relation to radioiodine uptake by the soil. Plural uptake mechanisms were considered for iodide species, while a simple anion exchange process for iodate.

96/05540 Ground level concentration of sulfur dioxide at Kuwait's major population centers during the oil-field fires

The uptake of radioiodide and iodate species by soil dried at 100 °C (particle size of less than 0.25 mm) was studied in laboratory batch experiments for three major groups of variables: (i) experimental conditions (ambient temperature, liquid-to-solid ratio and contact time), (ii) solid phase conditions (grain size and washing treatment), and (iii) liquid phase conditions (pH, and concentrations of electrolytes and carrier). Effects of the presence of soluble and insoluble organic matter were also investigated in relation to radioiodine uptake by the soil. Plural uptake mechanisms were considered for iodide species, while a simple anion exchange process for iodate.

Factors affecting interaction of radioiodide and iodate species with soil

The uptake of radioiodide and iodate species by soil dried at 100 °C (particle size of less than 0.25 mm) was studied in laboratory batch experiments for three major groups of variables: (i) experimental conditions (ambient temperature, liquid-to-solid ratio and contact time), (ii) solid phase conditions (grain size and washing treatment), and (iii) liquid phase conditions (pH, and concentrations of electrolytes and carrier). Effects of the presence of soluble and insoluble organic matter were also investigated in relation to radioiodine uptake by the soil. Plural uptake mechanisms were considered for iodide species, while a simple anion exchange process for iodate.

Chemical Behavior of Carrier Free Iodine Produced by Beta-Decay and Effects of Iodine Carriers

The effect of carriers oil the chemical behavior of 131I produced from the 130Te(n, γ)13lTe 131I processes was investigated with paper electrophoresis, autoradiography and γ-ray spectrometry. If no carrier was added, the chromatograms of the iodine species revealed significant deposits of an unexpected chemical species between the spots of the iodide and iodate species. The addition of either iodate or periodate as carrier converted the species into iodate in the former case, and into iodate and periodate in the latter. Referring to the already known exchange reactions between different iodine species, hence was concluded that the species observed in the experiment without carrier was the iodite species (IO− 2), as surmised by previous authors.