Determination of organic,inorganic and particulate iodine in the coastal atmosphere of Japan

A reliable method for the sampling and analysis of atmospheric iodine species was developed. The air filtering system consisted of a 0.4 m Nuclepore^® filter, 47 mm in diameter, for particulate collection followed by two, 47 mm in diameter, cellulose filters for inorganic iodine collection. The latter filters had been impregnated with 1N LiOH in a 10% glycerol-water mixture. The organic iodine was collected by two beds holding 0.2 g of fibriform activated charcoal produced from phenol resin. Supplementation of the charcoal with triethylendiamine (TEDA) enhanced the sorption ability for gaseous iodine. The filters were analyzed by neutron activation analysis. The background radioactivity could be reduced by using the fibriform activated charcoal due to the low content of impurities in the phenol resin. The background count for¹²⁸I (443 keV) obtained from the fibriform activated charcoal was about one order of magnitude lower than that of the conventional granular one (plant origin). Approximate detection limits for particulate, inorganic and organic iodine were 1, 0.5 and 0.5 ng/m³, respectively, when 50 m³ of air was sampled by this system. The air was sampled at two locations along the coast of Ibaraki, Japan. The concentration ranges of particulate, inorganic and organic iodine were 0.3–3.4, 1.2–3.3 and 7.8–20.4 ng/m³, respectively. Almost 90% of the atmospheric iodine was in a gaseous form in which organic iodine was dominant.     

The collection and determination of atmospheric gaseous bromine and iodine

A procedure has been developed which allows for the isolation, collection and analysis of atmospheric gaseous iodine and bromine. Particulate matter is removed from the airstream to be sampled by electrostatic precipitation. The gaseous halogen species are adsorbed onto specially cleaned activated charcoal. After irradiation of the charcoal sample with thermal neutrons, the iodine and bromine are removed from the charcoal, isolated, and purified as the AgX precipitate. The amounts of gaseous iodine and bromine are then determined by β-counting. The system works well for air sheds with low particulate iodine and bromine concentrations relative to that in the gaseous phase. In air sheds where the particulate halogen predominates, the gas phase measurements are more uncertain.     

Determination of iodine in human brain by epithermal and radiochemical neutron activation analysis

Despite the role of iodine for proper development of the brain and the functions of the element, the accurate data on its concentration in brain tissue are largely lacking, the main reason being analytical difficulties associated with determination of the element especially at low levels. In this work, samples from human brain regions from Hungarian patients were analyzed using epithermal and radiochemical neutron activation analysis (ENAA and RNAA, respectively). The RNAA procedure is based on alkaline-oxidative fusion followed by extraction of elemental iodine in chloroform. The results were checked by the analysis of biological standard reference materials, namely bovine liver, bone meal and diet, and by comparison with previous results obtained by a different RNAA procedure.     

Characterization of iodine species in the marine aerosol: To understand their roles in particle formation processes

In this contribution, iodine chemistry in the Marine Boundary Layer (MBL) is introduced. A series of methodologies for the measurements of iodine species in the gas and particle phases of the coastal atmosphere has been developed. Iodine species in the gas phase in real air samples has been determined in two field campaigns at the west coast of Ireland, indicating that gaseous iodo-hydrocarbons and elemental iodine are the precursors of new particle formation. Particulate iodine speciation from the same measurement campaigns show that the non-water-soluble iodine compounds are the main iodine species during the marine particle formation. A seaweed-chamber experiment was performed, indicating that gaseous I₂ is one of the important precursors that lead to new particle formation in the presence of solar light in the ambient air at the coastal tidal area.     

Efficiency of an in-line charcoal filter in automated chemistry process control unit during the synthesis of18F-fluorodeoxyglucose (FDG)

¹⁸F fluoride ion is produced by bombarding¹⁸O enriched water using an 11 MeV negative ion Radioisotope Delivery System (RDS-112) cyclotron by¹⁸O(p,n)¹⁸F reaction. During the synthesis of¹⁸F-FDG, a gaseous effluent containing¹⁸F is released. To quantitate the loss of¹⁸F during the synthesis, the¹⁸F activity at the end of bombardment delivered to chemical process control unit (CPCU), the amount of¹⁸F-FDG produced, the residual activity in CPCU, the activity trapped in charcoal filter, reaction vessels, cartridge and resin column were measured. A dose calibrator was used to assay total¹⁸F delivered to the CPCU and FDG produced. All other measurements were with a calibrated ionization chamber in a fixed geometry. The amount of gaseous¹⁸F released was calculated. For routine productions, conversion of¹⁸F into FDG was 46.0±4.0%. In six production runs without a charcoal filter, the mean gaseous release of¹⁸F was 10.6±1.0%. With an activated charcoal filter retrofitted to the exhaust of the CPCU, then mean gaseous¹⁸F activity released was 1.2±1.2%. The residual activity in the synthesis unit was 12.9±3.5%. The remaining activity i.e. 33.1±4.2%, was in the reaction vessels, cartridges and in the resin column. The efficiency of a charcoal filter for trapping¹⁸F gaseous effluent during synthesis was found to be >99.0%.     

Determination of atmospheric iodine species using a system of specifically prepared filters and IDMS

Summary A system was developed which allowed the determination of four different atmospheric iodine species by preparing glass microfibre filters, which were arranged in consecutive order, in a specific way. Particulate iodine was collected by a particle filter, HI and I₂ by a NaOH impregnated filter, HOI was adsorbed on a TBAH impregnated filter and organoiodine was adsorbed on a filter loaded with activated charcoal. These behaviours were checked by extensive model experiments. Two or more filters of the same type were used in series to show the degree of collection of one iodine species. Two European samples, one of continental and one of marine origin, and two Antarctic samples were analysed by this filter system using isotope dilution mass spectrometry (IDMS) for quantification. The distribution pattern for the different iodine species is similar for the two European samples. Organoiodine is found to be the most abundant species whereas in Antarctica the HI/I₂ fraction is up to nearly 50% of the total iodine. The particulate iodine fraction is higher in Europe than in Antarctica, which is due to the low particle concentration in the remote area of Antarctica. The higher HI/I₂ and HOI fractions found at the North Sea compared with the continental sample indicate that the ocean is a primary source of these species. Concentrations in the range of (0.3–3.1) ng I/m³ were analysed for particulate iodine, (0.4–1.3) ng I/m³ for HI/I₂, (0.2–1.8) ng I/m³ for HOI and (0.4–7.6) ng I/m³ for organoiodine. The detection limits varied with the variances of the blank values of the different filters and lay between 0.02 ng I/m³ and 0.24 ng I/m³ using sample volumes of 70 m³ air.     

Dynamic Vapour Generation and Head Space Determination of m-XYLENE for Pharmacokinetic Studies

Abstract

A custom designed vapour generation-exposure chamber assembly and head space analysis method were evaluated for use in pharmacokinetic investigations. The predicted m-xylene concentration was within 1% of the average value measured by gas chromatography-flame ionization detection (GC-FID) in the glass exposure chamber during controlled vapourization of m-xylene. The concentration variability was ± 13% and 4% respectively, with and without rats in the chamber. Blood and tissue samples from male, Sprague Dawley rats exposed to 1100 ppm of xylene, were analyzed by means of a static head space (HS)-GC analysis method. The average m-xylene level in the blood of exposed animals was ca. 5000 ng/mL. m-Xylene was detected in brain, kidney, skin, fat and liver. The analytical precision for duplicate samples was < ± 5% for all tissues, except liver and skin. The feasibility of detection of m-xylene in unhomogenized tissue by HS-GC analysis was demonstrated.     

Determination of iodine in Asian diets by epithermal and radiochemical neutron activation analysis

Samples of diets from China, Japan, Korea, India, Pakistan and Philippines were analyzed using epithermal and radiochemical neutron activation analysis (ENAA and RNAA, respectively) within the framework of the IAEA project “Reference Asian Man”. The RNAA procedure was based on alkaline-oxidative fusion followed by extraction of elemental iodine in chloroform. The analytical methods employed are discussed in terms of detection limits and uncertainties of the results obtained. For quality control purposes a number of NIST biological reference materials, namely diets and foods were analyzed. Results for the diet samples indicate that achieving the WHO recommended daily allowance for iodine may be a problem in most of the above given countries. This revised version was published online in August 2006 with corrections to the Cover Date.     

Clean conditions for the determination of ultra-low levels of mercury in ice and snow samples

Laboratory facilities and methods are presented for the determination of ultra-low levels of mercury (Hg) in ice and snow samples originating from polar ice caps or temperate regions. Special emphasis will be given to the presentation of the clean laboratory and the cleaning procedures. The laboratory is pressurized with air filtered through high efficiency particle filters. This first filtration is not enough to get rid of contamination by Hg in air. Experiments are conducted in a clean bench, especially built for Hg analysis, equipped with both particle filter and activated charcoal filter. It allows to obtain very low levels of atmospheric Hg contamination. Ultrapure water is produced for cleaning all the plastic containers that will be used for ice and snow samples and also for the dilution of the standards. Hg content in laboratory water is about 0.08+/-0.02 pg/g. A Teflon system has been developed for the determination of Hg in ice and snow samples based on Hg(II) reduction to Hg(0) with a SnCl2/HNO3 solution followed by the measurement of gaseous Hg(0) with a Hg analyzer GARDIS 1A+ based on the Cold Vapor Atomic Absorption Spectroscopy method. Blank determination is discussed.     

Occurrence,evolution and degradation of heavy haze events in Beijing traced by iodine-127 and iodine-129 in aerosols

Heavy haze events have become a serious environment and health problem in China and many developing countries, especially in big cities, like Beijing. However, the factors and processes triggered the formation of secondary particles from the gaseous pollutants are still not clear, and the processes driving evolution and degradation of heavy haze events are not well understood. Iodine isotopes (¹²⁷I and ¹²⁹I) as tracers were analyzed in time series aerosol samples collected from Beijing. It was observed that the ¹²⁷I concentrations in aerosols peaked during the heavy haze events. The conversion of gaseous iodine to particular iodine oxides through photochemical reactions provides primary nuclei in nucleation and formation of secondary air particles, which was strengthened as the external iodine input from the fossil fuel burning in the south/southeast industrial cities and consequentially induced heavy haze events. Anthropogenic ¹²⁹I concentrations peaked during clean air conditions and showed high levels in spring and later autumn compared to that in summer. ¹²⁹I originated from the direct air discharges and re-emissions from contaminated seawaters by the European nuclear fuel reprocessing plants was transported to Beijing by the interaction of Westerlies and East Asian winter monsoon. Three types of mechanisms were found in the formation and evolution of heavy haze events in Beijing by the variation of ¹²⁷I and ¹²⁹I, i.e., iodine oxides intermediated secondary air particles, dust storm and mixed mode by both secondary air particles and dust storm induced processes.     

Trapping of volatile iodine by an activated carbon fiber filter

Model experiments for a simple and effective trapping device of volatile iodine that is generated during radioiodination of biomacromolecules were performed using an activated carbon fiber filter. Over 99.9% of the radioactivity was trapped by the first sheet, when a stream of the volatile radioactive iodine was passed through the layer consisting of several sheets of carbon fiber filter of pore-size 2nm preceded by two or three sheets of urethane foam filter to eliminate the water vapor. Since the carbon fiber filter has very little resistance to the gas flow, the device seems applicable to the small filter chamber for the radioiodination hood.     

Comparative determination of bromine and iodine in three air sampling media via instrumental thermal and epithermal neutron activation analysis

A comparative determination of bromine and iodine in three distinct air sampling media by instrumental thermal and epithermal neturon activation analysis is presented. Open ocean air samples from the mid-Atlantic region were collected on ultra-pure nylon, Nuclepore, and activated charcoal substrates. The bromine and iodine content of each substrate was determined by both epithermal and thermal activation techniques. Good agreement was found within most thermal-epithermal pairs. Relative to the thermal activation procedure, the epithermal technique yields peak/background ratio improvements ranging from a factor of 1.30 to 9.5. Nylon substrates showed the smallest improvement at 1.30 and both Nuclepore and activated charcoal substrates showed improvement factors of 6.7 and 9.5 for bromine and iodine respectively.     

Zeolite imidazole framework-8(ZIF-8) decorated keratin-based air filters with formaldehyde removal and photocatalytic disinfection performance

Air pollution, consisting of particles of broad sizes, bioaerosols, and gaseous toxic chemicals, has become a serious hazard to public health. However, conventional fibrous filters have the disadvantages of high air resistance and limited ability to remove toxic gaseous and inhibit harmful microorganisms. Herein, we report a bilayer multifunctional air filter material based on applying electrospinning and needle-punching methods to generate hierarchically structure. Specifically, the air filter consists of keratin-based nanofibers as an upper layer and ZIF-8-modified polyethylene terephthalate/polyethylene needle-punched materials as the substrate. Green, facile, and controllable sonication process involved in thermally-assisted coating method was used to incorporate ZIF-8 onto the substate. The exposed functional groups of keratin and porous ZIF-8 nanocrystals with a high surface area promote the capture capability for small particulate pollutants and toxic gaseous molecules. Meanwhile, the needle-punched substrate with large pores significantly reduces the pressure drop and imparts photocatalytic disinfection performance to the air filter by the excellent photocatalytic characteristic of ZIF-8. This study proposes a novel strategy to fabricate hierarchical multifunctional air filters by combining electrospinning and needle-punching and plays a guidance role in designing and developing keratin-based hybrid materials.     

Clean conditions for the determination of ultra-low levels of mercury in ice and snow samples

Laboratory facilities and methods are presented for the determination of ultra-low levels of mercury (Hg) in ice and snow samples originating from polar ice caps or temperate regions. Special emphasis will be given to the presentation of the clean laboratory and the cleaning procedures. The laboratory is pressurized with air filtered through high efficiency particle filters. This first filtration is not enough to get rid of contamination by Hg in air. Experiments are conducted in a clean bench, especially built for Hg analysis, equipped with both particle filter and activated charcoal filter. It allows to obtain very low levels of atmospheric Hg contamination. Ultrapure water is produced for cleaning all the plastic containers that will be used for ice and snow samples and also for the dilution of the standards. Hg content in laboratory water is about ¶0.08 ± 0.02 pg/g. A Teflon system has been developed for the determination of Hg in ice and snow samples based on Hg(II) reduction to Hg(0) with a SnCl₂/HNO₃ solution followed by the measurement of gaseous Hg(0) with a Hg analyzer GARDIS 1A+ based on the Cold Vapor Atomic Absorption Spectroscopy method. Blank determination is discussed.     

X-ray fluorescence spectrometry applied to the analysis of environmental samples

X-ray fluorescence spectrometry is an expanding technique in the field of environmental analysis for both air and water pollution studies. Its capabilities now include the determination of gaseous contaminants in air in addition to the established area of elemental analysis, covering airborn particulates and soluble trace elements in water.     

Anionic graft polymerization of propylene sulfide on cellulose. II. Absorption of iodine,silver, and mercury on the graft polymers

The adsorption of iodine, silver nitrate, and mercuric chloride by cellulosic membranes grafted with polypropylene sulfide was investigated. It was found that the grafted polypropylene sulfide adsorbed iodine by complexation from aqueous solution or from gaseous phase. Adsorption from water led to the formation of a complex with molar ratio of I₂ to propylene sulfide units of 1, and that while the complex formed from gaseous iodine had a molar ratio I₂ to propylene sulfide approaching 2. Most of the sulfide groups participated in complexation. It was found that the complexation of the polysulfide was accompanied by degradation which was attributed to halogenation of the polysulfide at the tertiary carbon atoms. The iodine complex was more stable in water than in organic solvents, where most of the iodine was desorbed. The graft polymers adsorbed also by complexation silver nitrate and mercuric chloride. Adsorption could be described by a Freundlich type isotherm. At low concentrations most of the silver nitrate present in solution was adsorbed.     

Urban air pollutants and their micro effects on medieval stained glass windows

Levels of urban gaseous and particulate pollutants were investigated in the Cathedral of Cologne, Germany in the framework of the EU-project “VIDRIO”. The purpose of this study was to evaluate the influence of a protective double glazing system on the preservation of ancient stained glass windows by sampling at protected and unprotected windows (indoors, in the interspace and outdoor of the Cathedral). The interspace between the ancient stained glass window and the protective glazing is flushed in the Cathedral by indoor air, hence isolating the historic glass from the outdoor air and exposing it to indoor air on both sides of the glass panels. Concentrations of aggressive gaseous pollutants such as NO₂, SO₂, O₃ and CO₂ as well as elemental concentrations of bulk particles and relative abundances of single particles were surveyed at all sampling locations. Elemental concentrations in bulk particulate matter were found to be significantly lower inside the Cathedral in comparison to the outdoor air. This result is advantageous for the stained glass windows. Single particle analysis of the samples from Cologne showed also soil dust and organic particles as well as sulphates and nitrates, from which the latter two compounds are dangerous for the stained glass windows. On the base of the obtained results, it can be concluded that the protective glazing system in the Cathedral of Cologne can be considered as predominantly advantageous from both the gases' point of view (except for NO₂-candles burning) and from the particles' point of view.     

Epithermal neutron activation analysis using a boron carbide irradiation filter

The use of boron carbide as a thermal neutron filter in epithermal neutron activation (ENAA) analysis has been investigated. As compared to the use of a cadmium filter, boron provides a greater reduction of activities from elements relatively abundant in terrestrial rocks and fossil fuels, such as Na, La, Sc and Fe. These elements have excitation functions which follow the 1/v law in the 1 to 10 eV lower epithermal region. This enhances the sensitivity of ENAA for elements such as U, Th, Ba and etc. which have strong resonances in the higher epithermal region above 10 eV. In addition, a boron carbide filter has the advantages over cadmium of acquiring a relatively low level of induced activity which poses minimal radiation safety problems, when used for ENAA.     

Determination by activation analysis of volatile metals and other elements in volcanic exhalations collected at Vulcano and Stromboli,Italy

Hot gases of volcanic origin (fumaroles) were sampled by means of an activated charcoal filter. The charcoal was specially prepared by a high temperature-vacuum treatment. Mercury, arsenic, bromine, antimony and selenium were determined by activation analysis and compared with literature values. A lightweight pumping station was developed to enable transport to the crater regions of Stromboli and Vulcano. The teflon membrane pump is driven by wind. The filter unit, a specially shaped quartz glass tube, was lowered into the hot vents. The temperature of the sampled fumaroles was 100 to 330°C.