The determination of iodine in biological and environmental standard reference materials

Iodine is an element with excellent intrinsic sensitivity when determined by thermal neutron activation. However, in most real samples, the preponderance of chlorine and bromine, relative to iodine, makes the direct determination of iodine virtually impossible. Over the past 20 years, there probably have been as many publications on the separation of iodine as there have been for any other radionuclide. Upon review, however, the methods are essentially the same. After irradiation, the samples are subjected to a rapid destructive process to free the iodine from the matrix and then the iodine is separated from the other halides either by liquid-liquid extraction or by liquid ion exchange. Both of these procedures are, however, rather complex and do not effect a complete separation of the halides in one pass. In the work presented here, a simple procedure is described for the quantitative separation of iodine from chlorine. The procedure utilizes a gas phase separation on hydrated manganese dioxide with iodine collected on silvered quartz wool. The described procedure has been used for the determination of iodine in numerous new and old SRM's at the NBS.     

Use of neutron activation analysis in determination of total organic chlorine and bromine

Neutron activation analysis is practically the only high-sensitivy element-selective detection method for chlorine, bromine and iodine. This method is just ideal for organic halogen determination after separation of organically bound species from inorganic. In recent years we have analysed organic chlorine and bromine from thousands of different kind of samples with different separation methods. For water samples we have used activated-carbon adsorption and for solid samples mostly propanone or combined alkaline/propanone extraction before activated-carbon adsorption. Inorganic chlorides were removed from the carbon by nitrate wash. The detection limits for total organic chlorine and bromine are 5 and 0.5 g/l for water (sample size 100 ml) and 0.3 and 0.1 g/g dry weight (sample size 1 g) for sediment.     

Determination of bromine in organic compounds by high-performance liquid chromatography

A method is proposed for the determination of bromine in organic compounds (which may also contain chlorine and iodine) by oxygen-flask combustion of the compound followed by pre-column reaction of bromide with acetanilide and 2-iodosobenzoic acid to form 4-bromoacetanilide which is then chromatographed on an ODS column with a mobile phase of methanol: water, 65:35 v/v, detection at 240 nm, and 4-N-acetylaminotoluene as internal standard. The method is rapid and precise (RSD 相似文献   

Differentiation of the halogen content of peat samples using ion chromatography after combustion (TX/TOX-IC)

The proposed method for the differential AOX analysis of water samples was tested for its applicability to differentiate the halogen content of peat samples. For determination of the total and the total organic-bound chlorine, bromine and iodine, peat samples were combusted, and the combustion gases trapped and analyzed by ion chromatography (TX/TOX-IC). The total and the organically bound chlorine, bromine and iodine, respectively, can be determined by two-fold analysis with deviations of around 10%. With respect to chlorine more than a double determination could be required. The limit of quantification is 20 mg kg(-1) for chlorine, 2 mg kg(-1) for bromine and 1 mg kg(-1) for iodine, if 25 mg of peat is combusted. The most crucial step of the analysis is the inorganic halogen removal, which is necessary if the organically bound fraction is determined. However, there are some uncertainties about the complete removal of the inorganic halides from the solid samples. Thus, the values of the organically bound fraction have to be discussed as maximal concentrations. Nevertheless, we suggest that the applied method can be useful as a tool for studying the fate of halogens in soils.     

Determination of bromine and iodine in biological and environmental materials using epithermal neutron activation analysis

Epithermal neutron activation analysis (ENAA) was applied to the determination of the contents of bromine and iodine in 40 biological and environmental standard reference materials and Chinese diets. Boron nitride (BN) for solid samples and BN+Cd for liquid samples were adopted as shield material. Irradiation was carried out in inner and outer irradiation sites in a Miniature Source Reactor (MNSR) for solid and liquid samples, respectively. The 443 keV photopeak of ¹²⁸I and the 616 keV photopeak of ⁸⁰Br were used. The precision of measurement (relative standard deviation) is 2∼6% for contents of iodine of more than 100 ng/g and 8∼12% in the 20∼100 ng/g range in solid samples, and 12∼18% at less than 100 ng/ml in liquid samples. For bromine, the precision of measurement is 2–8% for solid samples and lower than 13% for liquid samples. The detection limits under experimental conditions varied between 10∼30 ng/g, 55∼95 ng/g and 25∼68 ng/g for iodine and 50∼150 ng/g, 200∼450 ng/g and 100∼300 ng/g for bromine in ENAA with BN shield in inner irradiation sites, with Cd shield and BN+Cd shield in outer irradiation sites, respectively. Received: 13 June 1996 / Revised: 2 September 1996 / Accepted: 19 September 1996     

Comparative study of activation analyses for the determination of trace halogens in geological and cosmochemical samples.

Halogens (fluorine, chlorine, bromine and iodine) were determined by activation analyses (neutron activation analysis (NAA), photon activation analysis (PAA) and prompt gamma-ray analysis (PGA)) for geological and cosmochemical solid samples. We studied how each analytical method was for the determination of trace amounts of halogens in rock samples. Radiochemical NAA (RNAA) showed the highest analytical reliability for three halogens (chlorine, bromine and iodine), whereas a set of four halogens (fluorine, chlorine, bromine and iodine) could be determined in principle by radiochemical PAA (RPAA) from a single specimen. Although it is a non-destructive method, PGA showed an analytical sensitivity for chlorine comparable to those of RNAA and RPAA.     

Simultaneous microdetermination of iodine and chlorine or iodine and bromine in organic compounds

Summary A micromethod for simultaneous determination of iodine and chlorine or iodine and bromine in organic compounds is described. After combustion in an oxygen-filled separatory funnel containing acidic sodium nitrite, iodine is produced, separated by carbon tetrachloride and oxidised with bromine water to iodate. After removal of carbon tetrachloride and excess bromine, the iodate is determined iodometrically. The aqueous combustion product is determined mercurimetrically for either chlorine or bromine. The average recoveries are 98.7%, 100.7% and 100.6% with iodine, chlorine and bromine in mixtures of their organically bounded compounds respectively. Microdetermination of iodine in presence of other halogens using sodium nitrite as absorbing agent andLeipert's method is described.

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Zusammenfassung Eine Mikromethode zur gleichzeitigen Bestimmung von J und Cl oder J und Br in organischen Verbindungen wurde beschrieben. Nach der Verbrennung in einem sauerstoffgefüllten Scheidetrichter in Anwesenheit angesäuerter Natriumnitritlösung wird Jod freigesetzt, mit Tetrachlormethan extrahiert und mit Bromwasser zu Jodat oxydiert. Nach Entfernung des Tetrachlorkohlenstoffs und des Bromüberschusses wird das Jodat jodometrisch titriert. In der wäßrigen Lösung wird mercurimetrisch Chlor bzw. Brom bestimmt. Die durchschnittliche Ausbeute beträgt 98,7, 100,7% und 100,6% für Jod, Chlor bzw. Brom in Gemischen ihrer organischen Verbindungen. Die Mikrobestimmung des Jods in Gegenwart anderer Halogene nach Absorption in Nitritlösung nach der Methode vonLeipert wurde beschrieben.

     

Determination of halogen species of humic substances using HPLC/ICP-MS coupling

A mass spectrometric method for the determination of chlorine, bromine and iodine species of humic substances (HS) has been developed by coupling a HPLC system with ICP-MS. Using size exclusion chromatography, the method was applied to the characterization of natural water samples (ground water, seepage water from soil, brown water) and a sewage water sample. Quantification of iodine/HS species was carried out by the on-line isotope dilution technique, which was not possible for bromine and chlorine species because of mass spectroscopic interferences by using a quadrupole ICP-MS. Characteristic fingerprints of the halogen/HS species, correlated with the corresponding UV chromatogram, were obtained dependent on the different origin of HS. Biological influences were indicated when following changes of the iodine/HS species composition by aging. The formation of iodine/HS species from inorganic iodide was investigated by labelling experiments with an ¹²⁹I^– spike solution, resulting in the finding that specific HS fractions are preferably iodinated.     

Relationship among iodine, bromine and chlorine concentrations in cow's milk in Japan

In order to know the relationship among some elements in biological materials, iodine, bromine and chlorine concentrations in cow's milk samples in Japan were determined by the thermal neutron activation analysis using a low power research reactor and a Van de Graaff accelerator. The iodine contents in cow's milk samples ranged from 0.041 to 0.316 ppm with an average of 0.096 ppm. The bromine and chlorine in these samples ranged from 2.3 to 11.1 ppm and from 475 to 1650 ppm, respectively. The average concentration of the bromine was calculated to be 5.6 ppm and that of the chlorine was 853 ppm. The relationship among iodine, bromine and chlorine concentrations in cow's milk samples in Japan was studied with a regression analysis. It was suggested that the correlation has a power function as follows; Y = K(Z)-A where, Y is elemental concentration in ppm, Z is atomic weight [corrected] of element, A (= 7.4) is exponent and K (= 14.7) is a constant.     

An atmospheric-pressure,argon-afterglow detector for gas chromatography

The development of an atmospheric-pressure argon-afterglow, produced from an ozonizer-type discharge tube, for element-selective, multielement detection in gas chromatography is described. Characteristic atomic emission is observed from chlorine, bromine, iodine, carbon, sulfur and phosphorus in organic compounds, with limits of detection ranging from 0.02 ng for phosphorus to 20 ng for bromine. Element-selective detection for several pesticides is demonstrated.     

Speciation of halogenides and oxyhalogens by ion chromatography-inductively coupled plasma mass spectrometry

A speciation method utilizing ion chromatography coupled with inductively coupled plasma mass spectrometry is described for simultaneous analysis of eight halogenides and oxyhalogens: chloride, chlorite, chlorate, perchlorate, bromide, bromate, iodide and iodate. The method was applied for the analysis of drinking water samples collected from water treatment plants in areas in Finland, which are known to have high bromine concentrations in ground water. Water samples collected before and after disinfection were analyzed to get information about potential species conversion as a result of purification. Chloride and chlorate were the chlorine species found in these water samples, and iodine existed as both iodate and iodide. In the case of bromine, species conversion had taken place, since total bromine concentrations were increased during disinfection but bromide concentrations were decreased. No bromate was observed in the samples. The detection limits for all the chlorine species studied were 500 μg/l, for bromine species studied 10 μg/l, for iodide 0.1 μg/l and for iodate 0.2 μg/l.     

Separation of bromo- and iodosubstituted thyronines by high-performance liquid chromatography

Summary A reversed-phase high performance liquid chromatographic method on C-18 bonded silica is described for the separation of trisubstituted iodo/bromothyronines, which exert thyroid hormone activity. The composition of the mobile phase has been systematically optimized resulting in a ternary mixture of methanol/acetonitrile/water acidified with trifluoroacetic acid. The applicability of ultraviolet absorption detection, amperometric detection and off-line radioimmunoassay was investigated. The latter method allows detection of the different iodo/bromothyronines down to 40–120 ng/l mobile phase; this sensitivity is high enough for application to thyroid hydrolysates in order to clarify the question as to whether bromine can substitute iodine in the biosynthesis of thyroid hormones.     

Determination of organophosphate flame retardants in soil and fish using ultrasound‐assisted extraction,solid‐phase clean‐up,and liquid chromatography with tandem mass spectrometry

A solid–liquid extraction method in combination with high‐performance liquid chromatography and tandem mass spectrometry was developed and optimized for extraction and analysis of organophosphorus flame retardants in soil and fish. Methanol was chosen as the optimum extraction solvent, not only in terms of extraction efficiency, but also for its broader analyte coverage. The subsequent clean‐up by solid‐phase extraction is required to eliminate matrix coextractives and reduce matrix effects. Recoveries of the optimized method were 50–121% for soil and 47–123% for biota, both with high precision (RSDs <12% in soil and <23% in biota). The method limits of detection ranged from 0.06 to 0.20 ng/g dry weight and between 0.02 and 0.30 ng/g wet weight for soil and biota samples, respectively. However, samples with a high lipid content produce several problems as solid‐phase extraction cartridge clogging that increase variability and analysis time. The method was successfully applied for the determination of organophosphorus flame retardants in soil and fish from L'Albufera Natural Park (Valencia, Spain). Target compounds were detected in all soil and fish samples with values varying from 13.8 to 89.7 ng/g dry weight and from 3.3 to 53.0 ng/g wet weight, respectively.     

A simplified method for the amplification of iodine

The sample solution is treated so that all iodine is present in the elemental state. This iodine is extracted into chloroform and thereby separated with very high selectivity from almost any matrix. Until now, in order to apply amplification via oxidation to iodate and reaction with iodide, a reextraction into a sodium hydroxide solution was necessary. In the new procedure the organic phase is shaken with bromine water. Thereby, the iodate formed moves completely into the water phase while the bromine accumulates in the chloroform. Remaining bromine in the water is destroyed with some formic acid. No buffer is needed, because the acid establishes the correct conditions for this reaction and also that between iodate and iodide. The iodine formed in sixfold amount can now be titrated visually or photometrically with thiosulfate or subjected to a second amplification cycle. The new procedure eliminates the reextraction, and the addition of some reagents especially sodium hydroxide which is the main contributor of extraneous iodine. Thus, the blank is reduced by a factor of 10 or more and is also more constant. Iodine at lower levels (< 1 μg/ml) can be determined and with higher reliability.     

Determination of chlorine, bromine and iodine in rock samples by radiochemical neutron activation analysis

Chlorine, bromine and iodine (hereafter, halogens) were detemined for rock samples by radiochemical neutron activation analysis. The powdered samples and reference standards prepared from chemical reagents were simultaneously irradiated for 10 to 30 minutes with or without a cadmium filter in a TRIGA-II reactor at the Institute for Atomic Energy, Rikkyo University. The samples were subjected to radiochemical procedures of halogens immediately after the irradiation. Iodine was firstly precipitated as PdI₂, and chlorine and bromine were successively precipitated as Ag-halides at the same time. In this study, geological standard rocks, sedimentary rocks and meteorites were analyzed for trace halogens. In some Antarctic meteorites, iodine contents were observed to be anomalously high. Chlorine contents also are somewhat high. The overabundance of iodine and chlorine must be caused by terrestrial contamination on the Antarctica.     

Assessment of the occurrence and distribution of pharmaceuticals in a Mediterranean wetland (L'Albufera, Valencia, Spain) by LC-MS/MS

The distribution of 17 pharmaceuticals between water and the solid phase (sediments and soils) was studied by utilizing solid-phase extraction (SPE) and liquid chromatography?Ctandem mass spectrometry (LC-MS/MS). Two extraction procedures for soils and sediments, prior to the SPE, one based on pressurized liquid extraction (PLE) with hot water and the other on methanol/water ultrasonic extraction, were compared. Absolute recoveries were 71.2?C99.3% [relative standard deviation (RSD) <21.4%)] for water, and the method detection limits (MDLs) ranged from 0.3 to 10?ng?L^?1. Recoveries were 35.4?C105.3% (RSDs <19.1%) and 42.1?C97.8% (RSDs <14%) for soil and sediment samples, respectively, using PLE and 20.2?C86.5% (RSDs <25.1%) and 30.3?C97.4% (RSDs <19.1%) using ultrasonic extraction. Fifteen of the 17 pharmaceuticals were present in the L??Albufera water at concentrations up to 17???g?L^?1. Oxytetracycline and tetracycline were not detected. In sediments, only tetracycline, norfloxacin and diclofenac were not found. The other studied pharmaceuticals were present in the range from less than the method quantification limit (MQL) to 35.83?ng?g^?1. Among the 17 target compounds, ofloxacin, ciprofloxacin, norfloxacin, trimethoprim, clofibric acid and diclofenac were not detected in soil samples. The average concentrations ranged from less than the MQL for ibuprofen to 34.91?ng?g^?1 for tetracycline. These results indicate that pharmaceuticals could survive the wastewater treatment processes, which could lead to their dissemination in water environments.     

Degree of solid-phase oxidation of nickel and cobalt phthalocyanines by halogens

Electronic and IR transmission spectroscopy and ESR have been used to investigate the products obtained in the oxidation of layes of nickel and cobalt phthalocyanines by halogen vapors. It has been established that cobalt phthalocyanine in chlorine or bromine vapor forms stable cation radicals in which one electron has been detached from the cobalt and the other from the phthalocyanine ligand; in iodine vapor, a partially oxidized product is formed, with a positive charge on the ligand. Nickel phthalocyanine in bromine vapor at high pressure of bromine, and also in chlorine or iodine vapor, nickel phthalocyanine forms partially oxidized products with various degrees of oxidation of the ligand. An interpretation is given for the spectra of the ionic species that have been investigated; the interpretation can be used in particular to determine the degree of the ionic species on the basis of their spectra.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 5, pp. 528–534, September–October, 1989.The authors wish to thank A. V. Baranov for measuring the Raman spectrum of the bromine-oxidized Copc.     

Supported liquid membrane work-up in combination with liquid chromatography and electrochemical detection for the determination of chlorinated phenols in natural water samples

Summary A sample preparation method has been developed for the determination of chlorinated phenols in water. The method is based on a supported liquid membrane extraction system connected on-line to liquid chromatography with electrochemical detection. The supported liquid membrane technique utilizes a porous PTFE membrane. The membrane is impregnated with an organic solvent which forms a barrier between two aqueous phases and enables selective extraction. The technique can easily be coupled in a flow system. In this investigation five chlorinated phenols (1–5 chlorine atoms) were extracted from natural water samples. Extraction for 30 minutes resulted in detection limits of approximately 25 ng L^–1.     

Determination of multi‐class antibiotic residues in compost by microwave‐enhanced accelerated solvent extraction and ultra performance convergence chromatography with tandem mass spectrometry

This work reports the development and application of a multi‐class compound analysis method for the determination of 20 antibiotic residues in compost. Samples were processed by microwave‐enhanced accelerated solvent extraction at 120°C for 7.5 min. Salting‐out homogeneous liquid‐liquid extraction was used to remove water and water‐soluble impurities from the extract before ultra performance convergence chromatography with tandem mass spectrometry analysis. By using the supercritical fluid (carbon dioxide) and organic solvent (methanol) as the mobile phase, the 20 antibiotics and the internal standard were well separated in 8.2 min without obvious matrix effect. Method validation was performed and good trueness (relative error in the range of ±5.0%) and precision (inter‐ and intraday relative standard deviations < 10.8%) were obtained. Method detection and quantitation limits were 0.8–1.9 and 2.7–7.1 ng/g, respectively. Recoveries were assessed at three concentration levels (10, 60, and 400 ng/g) and acceptable mean values (70.4–111.9%) were found. This method has also been used to analyze real samples, and the average concentrations of antibiotics (excepting the concentrations < method quantitation limits) were determined up to 123.6 ng/g. The results showed the method could be helpful for the analysis of multi‐class antibiotics in environmental samples.     

Rapid IC-ICP/MS method for simultaneous analysis of iodoacetic acids, bromoacetic acids, bromate, and other related halogenated compounds in water

Haloacetic acids (HAAs) and bromate are toxic water disinfection by-products (DBPs) that the U.S. Environmental Protection Agency has regulated in drinking water. Iodoacetic acids (IAAs) are the emerging DBPs that have been recently found in disinfected drinking waters with higher toxicity than their corresponding chloro- and bromo-acetic acids. This study has developed a new rapid and sensitive method for simultaneous analysis of six brominated and four iodinated acetic acids, bromate, iodate, bromide, and iodide using ion chromatography-inductively coupled plasma-mass spectrometry (IC-ICP-MS). Mono-, di- and tri-chloroacetic acids are not detected by this method because the sensitivity of ICP-MS analysis for chlorine is poor. Following IC separation, an Elan DRC-e ICP-MS was used for detection, with quantitation utilizing m/z of 79, 127, and 74 amu for Br, I, and Ge (optional internal standard) species, respectively. Although the primary method used was an external standard procedure, an internal standard method approach is discussed herein as well. Calibration and validation were done in a variety of natural and disinfection-treated water samples. The method detection limits (MDLs) in natural water ranged from 0.33 to 0.72 μg L⁻¹ for iodine species, and from 1.36 to 3.28 μg L⁻¹ for bromine species. Spiked recoveries were between 67% and 123%, while relative standard deviations ranged from 0.2% to 12.8% for replicate samples. This method was applied to detect the bromine and iodine species in drinking water, groundwater, surface water, and swimming pool water.