Determination of iodine and bromine in plasma and urine by inductively coupled plasma mass spectrometry

The simultaneous determination of iodine and bromine in plasma and urine by inductively coupled plasma mass spectrometry, using a Nermag prototype instrument, is described. The sample preparation involves only a 10-fold dilution with a diluent containing europium as an internal standard followed by direct nebulisation in the plasma. The iodine, bromine and europium ions are measured at m/z = 127, 79, and 153, respectively. The sensitivity of the method, with detection limits of 1.6 and 52 micrograms l-1 for iodine and bromine, respectively, is satisfactory for clinical applications. The calibration graphs were linear over the ranges 0-400 micrograms l-1 and 0-40 mg l-1 for iodine and bromine, respectively, which are wide enough for most assays. The recoveries were close to 100% with coefficients of variation of less than 3%. The within-day and between-day reproducibility was about 5%. The concentrations of iodine and bromine in the plasma of 26 healthy individuals were 58 +/- 12 micrograms l-1 and 4.1 +/- 0.9 mg l-1, respectively. The amounts of iodine and bromine eliminated in urine were 94 +/- 97 micrograms per 24 h (range 27-403 micrograms per 24 h) and 3.6 +/- 1.7 mg per 24 h, respectively. These results are in agreement with reported values.     

The simultaneous determination of silver,gold and mercury in high-purity lead by neutron activation analysis

A radiochemical method was developed to separate the group of the noble metals simultaneously from a lead matrix after irradiation with thermal neutrons. The resulting complex γ-spectrum was resolved by matrix calculus. Smoothing of the obtained data to determine the presence of small photopeaks among the background fluctuations, was done by convolution, based on a least squares approximation. The interference of antimony and bromine was studied. Amounts as low as 20–30 p.p.b. of Hg and less than 1 p.p.b. of Au were determined in the presence of up to 9 p.p.m. of Ag.     

Coulo-bipotentiometric titrations in the analysis of bromine in bromine-doped cadmium chalcogenides

The detection of bromine in the 60–1300 p.p.m. range in Cd-chalcogenideshas been proved feasible by a d.e.p. version of argentometric titration, where the titrant (silver ions) is coulo-generated. The analytical method described seems to meet the requirements of the simplicity necessary when routine work is needed and when small samples (about 20–100 mg) are available.     

Calculation of stoichiometric dissociation constants of monoprotic carboxylic acids in dilute aqueous sodium or potassium chloride solutions and p[m(H(+))] values for acetate and formate buffers at 25 degrees C

Equations are given for calculation of the stoichiometric (molality scale) dissociation constants, K(m), of weak acids in dilute aqueous electrolyte solutions at 298.15 K from the thermodynamic dissociation constant, K(a), of the acid and the ionic strength, I(m), of the solution. The equations for K(m) were based on the single-ion activity coefficient equations of the Hückel type. The equations were tested with the conductivity data for formic, acetic, propionic, n-butyric, lactic, chloroacetic, alpha-crotonic and cyanoacetic acids, and with data measured by Harned cells for formic, acetic, propionic, n-butyric and glycolic acids. These data were taken from the literature. According to these tests, K(m) can be obtained by the Hückel method within experimental error at least up to I(m) of about 0.1 mol kg(-1). On the basis of the equations for K(m), it is suggested p(m(H)) values {p(m(H))=-lg[m(H(+))/(mol kg(-1))] where m refers to the molality} for buffer solutions containing acetic or formic acid. A new calibration method is suggested for glass electrode cells, and this method is based on the p(m(H)) values instead of pH values (pH=-lg[a(H(+))] where a refers to the activity).     

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.     

Fluoroindenes. 10. Cyclization of difluorocarbene to perfluoro-3-methylindene and perfluoro-1-methyleneindane. Thermolysis and bromination of the resultant cyclopropane derivatives

Conclusions Upon reaction of perfluoro-3-methylindene and perfluoro-1-methyleneindane with hexafluoropropylene oxide at 225°C the corresponding cyclopropane derivatives are formed: perfluoro-la-methyl-1,1a,6,6a-tetrahydrocycloprop[a]indene and perfluorospiro[indane-1,1-cyclopropane], which are transformed during thermolysis in the presence of bromine into 1-bromo-2-difluorobromomethylperfluoro-1-methylindane and 1-bromo-1-(2-bromotetrafluoroethyl)perfluoroindane respectively, and in the absence of bromine into the starting olefins.Deceased.For previous report, see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1839–1845, August, 1988.     

Some investigations of fusing and dissolving samples

When both Si-H and Si-vinyl are present, the sum of these groups can be determined bromometrically. For Si-H a gasvolumetric method is applied and Si-vinyl results from the difference. The bromometric determination is carried out by dissolving the sample in a mixture of carbon tetrachloride/acetic acid, addition of excess solution of bromine in acetic acid and back-titration of the unconsumed bromine. Mercuric chloride serves as a catalyst for the bromine addition. The Si-H determination is carried out by measuring the hydrogen gas evolved after hydrolysis of the sample in wet n-butanol in the presence of sodium n-butanolate. The bromometric method proved to be also useful for the rapid and sensitive determination of either Si-vinyl or Si-H. The time required is 45 min, the lower limit is 0.02 mmole per g.     

Vergleichende Untersuchung der Bromaddition an symmetrisch substituierte Stilben- und Tolan-Derivate

The addition of bromine to multiple bond systems is generally maintained to be an electrophilic reaction. Assuming an electrophilic mechanism however leads to difficulties with reactions on the CC triple bond system. In addition, the few existing investigations show a strong influence of trace contaminations. Through the principle of preliminary reactions, proven in polymer reactions, it was possible to obtain pure bromobenzene solutions of stilbene, tolane, p,p′-dimethyl-stilbene and-tolane, m,m′-dimethyl-stilbene and-tolane, p,p′-dibrom-stilbene and-tolane, m,m′-dinitro-stilbene and-tolane, p,p′-dinitro-stilbene and-tolane, as well as of bromine. With such solutions, for all cases of brominations, the rate law obtained ([c] = concentration of unsaturated compound) was

$$d[Br_2 ]/dt = d[c]/dt = k[Br_2 ]^2 [c]$$     

Study on the surface density of surface-active substances through total-reflection X-ray absorption fine structure measurement

The total-reflection X-ray absorption fine structure (XAFS) method previously employed for the adsorption of dodecyltrimethylammonium bromide (DTAB) at the air/water interface was applied to that in the presence of NaBr. The surface concentration of the bromide ions Gamma(X)(B) of DTAB and NaBr was evaluated by using the Br K-edge absorption jump values of the total-reflection XAFS spectra and was compared to the corresponding value Gamma(H)(B) estimated from the dependence of surface tension on the bulk concentrations of DTAB m(1) and NaBr m(2). The Gamma(X)(B) values trace almost perfectly the Gamma(X)(B) versus m(1) curve up to a concentration near the critical micelle concentration (cmc) and deviate gradually above the concentration. This behavior is basically similar to that of the single DTAB system and ensures that the XAFS method is also applicable to the DTAB system, even in the presence of NaBr. In addition, this method was extended to the single nonionic amphiphile with covalently bonded bromine, and the surface concentrations of 6-bromo-1-hexanol (BrC6OH), Gamma(X)(1) and Gamma(H)(B), were evaluated and compared with each other. It was found that the Gamma(X)(1) value almost perfectly traces the Gamma(H)(1) versus m(1) curve, even at high surface concentrations. The excellent coincidence confirmed that the total-reflection XAFS method can be applied to the nonionic amphiphile system as well as a cationic surfactant with or without an added salt system. Finally, the difference between the Gamma(X)(B) and Gamma(H)(B) values observed in the DTAB with and without an added salt system is briefly described.     

On-line speciation of bromine and bromide using sequential injection analysis with spectrophotometric detection

An on-line procedure for the simultaneous determination of bromine and total bromine (bromine+bromide oxidised to bromine) is proposed, which lead to the determination of bromide by subtraction. Phenol red was used as chromogenic reagent for bromine and total bromine after bromide was oxidised to bromine by Chloramine T. The linear range found is 1-10 mg L(-1) with a detection limit of 0.6 mg L(-1) for bromine, and a linear range of 0.8-15 mg L(-1) with a detection limit of 0.4 mg L(-1) for total bromine. The calculated RSD for bromine is less than 0.8% and for total bromine less than 0.7%. The system is fully computerised and able to run 30 samples per hour with an automated rinsing step that eliminates sample carry-over. The results for both bromine and bromide from the proposed sequential injection analysis (SIA) system compare favourably with standard manual methods and statistical evaluation proves no significant difference between the results of the proposed SIA system and the standard method at the 95% confidence level. The presence of other halides was found not to interfere.     

The determination of rubidium by the method of stable isotope dilution

The rubidium contents of a granite (G-1), a diabase (W-1) and sea-water have been determined by mass spectrometric isotope dilution analysis. The values found are: G-1, 214 p.p.m-; W-1, 21.3 p.p.m.; sea water, 121.4 μg/l. These results show excellent agreement with values obtained at Harwell by neutron activation analysis, and the coefficient of variation for four determinations is usually ±1–2%.Rubidium ions were produced in the mass spectrometer by either a side filament or a centre filament technique. The former method enables rubidium and lithium determinations to be combined; the results obtained by the second method suggest that concentrations of the order of 1 p.p.m. may be determined for a sample of only a few mg with little chemical treatment beyond that required to decompose the sample.     

Systematic Study of Quaternary Ammonium Cations for Bromine Sequestering Application in High Energy Density Electrolytes for Hydrogen Bromine Redox Flow Batteries

Bromine complexing agents (BCAs) are used to reduce the vapor pressure of bromine in the aqueous electrolytes of bromine flow batteries. BCAs bind hazardous, volatile bromine by forming a second, heavy liquid fused salt. The properties of BCAs in a strongly acidic bromine electrolyte are largely unexplored. A total of 38 different quaternary ammonium halides are investigated ex situ regarding their properties and applicability in bromine electrolytes as BCAs. The focus is on the development of safe and performant HBr/Br₂/H₂O electrolytes with a theoretical capacity of 180 Ah L⁻¹ for hydrogen bromine redox flow batteries (H₂/Br₂-RFB). Stable liquid fused salts, moderate bromine complexation, large conductivities and large redox potentials in the aqueous phase of the electrolytes are investigated in order to determine the most applicable BCA for this kind of electrolyte. A detailed study on the properties of BCA cations in these parameters is provided for the first time, as well as for electrolyte mixtures at different states of charge of the electrolyte. 1-ethylpyridin-1-ium bromide [C2Py]Br is selected from 38 BCAs based on its properties as a BCA that should be focused on for application in electrolytes for H₂/Br₂-RFB in the future.     

DFT and ab initio dual-level direct dynamics studies on the reactions of fluorine atom with HOCl and HOBr

The multichannel reactions (1) HOCl + F --> products and (2) HOBr + F --> products have been investigated using the dual-level direct dynamics method. The minimum energy paths (MEPs) are calculated at both the MPW1K/6-311G(d,p) and QCISD/6-311G(d,p) levels, then the single-point energies are further corrected at the QCISD(T)/6-311++G(3df,3pd) level of theory. There are hydrogen-bonded complexes with the energies less than those of the reactants or products located at the entrance or exit channel of both hydrogen abstraction reactions; while for the halogen abstraction channels only one complex exists at the reactant side in the bromine abstraction channel. The rate constants are evaluated by the improved canonical variational transition-state theory (ICVT). The agreement of the rate constants with available experimental values for two reactions at room temperature is good. Theoretical results indicate that for the reaction HOCl + F, hydrogen abstraction channel leading to the formation of HF + ClO will predominate the reaction over the whole temperature range, and the reaction of HOBr + F may proceed mainly through the bromine abstraction channel at the lower temperature while the contribution of hydrogen abstraction channel will become significant as the temperature increases. Because of lack of the kinetic data of these reactions, the present theoretical results are expected to be useful and reasonable to estimate the dynamical properties of these reactions over a wide temperature range where no experimental value is available.     

Determination of iodine and bromine compounds in foodstuffs by CE-inductively coupled plasma MS

A CE-inductively coupled plasma mass spectrometric (CE-ICP-MS) method for iodine and bromine speciation analysis is described. Samples containing ionic iodine (I(-) and IO(3)(-)) and bromine (Br(-) and BrO(3)(-)) species are subjected to electrophoretic separation before injection into the microconcentric nebulizer (CEI-100). The separation has been achieved in a 50 cm length x 75 microm id fused-silica capillary. The electrophoretic buffer used is 10 mmol/L Tris (pH 8.0), while the applied voltage is set at -8 kV. Detection limits are 1 and 20-50 ng/mL for various I and Br compounds, respectively, based on peak height. The RSD of the peak areas for seven injections of 0.1 microg/mL I(-), IO(3)(-) and 1 microg/mL Br(-), BrO(3)(-) mixture is in the range of 3-5%. This method has been applied to determine various iodine and bromine species in NIST SRM 1573a Tomato Leaves reference material and a salt and seaweed samples obtained locally. A microwave-assisted extraction method is used for the extraction of these compounds. Over 87% of the total iodine and 83% of the total bromine are extracted using a 10% m/v tetramethylammonium hydroxide (TMAH) solution in a focused microwave field within a period of 10 min. The spike recoveries are in the range of 94-105% for all the determinations. The major species of iodine and bromine in tomato leaves, salt, and seaweed are Br(-), IO(3)(-), I(-), and Br(-), respectively.     

Neutron activation analysis of high purity Selenium: Determination of Bromine

Neutron activation analysis for 2–0.8 p.p.m. bromine in selenium was performed by irradiating i-g samples for 2 h at a neutron flux of 4.10¹¹ n/cm²/sec. The bromine was separated by a double precipitation technique as silver bromide to obtain adequate decontamination and the isotope ⁸²Br (T_{$\text{1}\text{2}$}=35.87 h) measured. Errors due to self-shielding in the standards and flux-depression in the selenium were calculated. Measurements on 2 different photopeaks were made to avoid errors from interfering isotopes.     

The determination of lithium in rocks by the method of stable isotope dilution

A method is described for the determination of lithium in rocks by the method of stable isotope dilution. 50 mg to 500 mg of the sample are used for each determination. The sample is mixed with a known quantity of enriched lithium and is then decomposed by a mixture of hydrofluoric and perchloric acids. The separation of the alkali metals from iron and aluminium is based on the thermal decomposition of the perchlorates. For mass spectrometric measurements it is not necessary to separate the lithium from the other alkali metals.The values obtained for the lithium contents of two standard rocks are: G-I, 21.3 p.p. m. ; W-I, 12.6 p.p.m. Independent determinations, made using both lithium 6 and lithium 7 as tracers, have established that no significant systematic errors are caused by isotopic fractionation.Results obtained for two clay samples containing 0.1–0.3% of lithium show good agreement with spectrographic values.     

Dosage de l'or spectrophotométrie d'absorption atomique sans flamme: Application aux minerais de zinc,de plomb et à leurs sous-produits

The application of flameless atomic absorption spectrometry to the determination of gold in raw sulfide ores of zinc and lead is described. After dissolution of the sample by a mixture of hydrochloric and nitric acids and bromine, gold is extracted by MIBK and the extract is submitted to atomization. The detection limit is estimated as 0.003 p.p.m. and the reproducibility as 4–5 % at the 2 p.p.m. level.     

The examination of bromine-containing fire retardants in unsaturated polyester resins by means of pyrolysis residue analysis

A method has been developed for following the bromine and weight losses of fire retarded UPE as a function of temperature. The results obtained by this method indicate that those bromine–containing fire retardants which exhibit a linear LOI–bromine concentration relation, the bromine concentration in the pyrolytically produced fuel remains more or less constant, while for those materials which deviate positively from the linear relation (that is they are more efficient), the bromine concentration in the fuel tends to peak at certain temperatures. When this effect is combined with variation in composition of the pyrolytic fuel, a situation can arise where a high bromine concentration coincides with a fuel particularly sensitive to flame quenching by bromine. Such a combined effect may be the reason why some brominated fire retardants are far more effective than others.     

Determination of chlorine and bromine in rocks by alkaline fusion with ion chromatography detection

This study describes the use of alkaline fusion by sodium peroxide to dissolve chlorine and bromine in rocks to produce a solution which, with appropriate pre-treatment, is suitable for analysis by ion chromatography. Results are given for a selection of sedimentary and igneous rocks. The accuracy of the fusion method is evaluated by analysis of Geological Survey of Japan reference materials. Additionally, a spike recovery test is performed to show that the fusion process is quantitative for chlorine and bromine. The results for chlorine are in the range 58–3860 mg kg⁻¹ and show good agreement both with results obtained by pyrohydrolysis with flow injection colorimetric detection and results obtained by aqueous leaching of the samples with ion chromatography detection. Results for bromine are in the range <3–4.5 mg kg⁻¹. Because of the relatively few data obtained in this study and the relative paucity of published data for reference materials, an assessment of the accuracy of the fusion method for bromine is more difficult. The limits of detection for this method are 36 and 3 mg kg⁻¹ for chlorine and bromine, respectively.     

Accurate measurement of bromine contents in plastic samples by instrumental neutron activation analysis

Accurate measurements of bromine contents in plastic samples were made by the direct comparator instrumental neutron activation analysis (INAA). Individual factors affecting the measurements were comprehensively evaluated and compensated, including the volatility loss of bromine from standard comparators, the background bromine level in the filter papers used for preparation of the standard comparators, nuclear interference, γ-ray spectral interference and the variance among replicates of the samples. Uncertainty contributions from those factors were thoroughly evaluated and included in the uncertainty budgeting of the INAA measurement. ⁸¹Br was chosen as the target isotope, and the INAA measurements for bromine were experimentally confirmed to exhibit good linearity within a bromine content range of 10–170 μg. The established method has been applied to the analysis of eight plastic samples: four commercially available certified reference materials (CRMs) of polyethylene and polystyrene and four acrylonitrile butadiene styrene (ABS) samples prepared as the candidate reference materials (KRISS CRM 113-01-012, -013, -014 and -015). The bromine contents of the samples were calculated at three different γ-ray energies and compared, showing good agreement. The results of the four CRMs also showed good consistency with their certified values within the stated uncertainties. Finally, the bromine contents of the ABS samples were determined with expanded uncertainties (at a 95% level of confidence) between 2.5% and 5% in a bromine content range of 25–900 mg kg⁻¹.