Individual microdetermination of chlorine, bromine and iodine in halogenated organic compounds by the oxygen-flask method

A simple and accurate micro-method for the individual determination of Cl, Br and I in halogenated organic compounds by the oxygen-flask method is described. Addition of potassium bromate to oxidize bromide, and of hydrogen peroxide to oxidize iodide, followed by boiling, is used to eliminate these two halides in mixtures with chloride or each other.     

Rapid radiochemical separation and determination of chlorine,bromine and iodine in water samples using ion exchange

On the basis of tracer experiments, a simple and rapid radiochemical separation method for simultaneous determination of I^–, Br^– and Cl^– in one aliquot of a water sample (only 2–4 ml) has been developed. The method is based on short irradiation of the water sample and separation of the halogens using sequential ion exchange columns filled with Dowex 1×8, 100–200 mesh anionic resin prepared in I^–/I₂, Br^–/Br₂ and Cl^– form. After washing the columns with an appropriate volume of 2% NaCl solution, the resins were transferred to vials and activities of the isolated radionuclides¹²⁸I,⁸²Br and³⁸Cl measured together with standards in a well type or on a coaxial Ge detector connected to a Canberra 90 multichannel analyzer. Besides high chemical yields, from the -spectra of the isolated radionuclides, it is evident that high decontamination fac-The paper was presented at the MTAA-8, Vienna, September 1991.     

A sensitive colorimetric method for the micro determination of iodine in marine water

More than 70% of the earth surface is covered by water bodies. Marine pollution is associated with the discharge of oils, petroleum products, sewage agricultural wastes, pesticides, heavy metals, waste substances and dumping of radioactive waters in sea. This in turn results in hazards to human health, hindrance to aquatic organisms and impairment of quality for use of sea water. Sea water is reported to contain iodine but the concentration varies according to the location and depth. Here a simple and sensitive method is described for the determination of iodine using leucocrystal violet as a reagent in different samples of sea water. The method is based on the oxidation of iodine to iodate with bromine water and the liberation of free iodine from the iodate by addition of potassium iodide in acedic medium. This iodine selectively oxidises leucocrystal violet to form the crystal violet dye. Beer's law is obeyed over the concentration range of 0.04-0.36 ppm of iodine at lambda(max) 592 nm. The dye was further extracted in chloroform. The extracting system obeys Beer's law in the range of 0.008-0.08 ppm at lambda(max) 588 nm.     

The simultaneous microdetermination of chlorine,bromine, and iodine in organic compounds by the oxygen flask method

Summary A method is described which allows the simultaneous microdetermination of chlorine, bromine and iodine following organic decomposition by the oxygen flask procedure ofSchöniger. Sodium borohydride is employed as a reducing agent in the absorbing solution. The sum of halogens is titrimetrically determined in an aliquot of the absorbing solution by means of 0.01N mercuric perchlorate solution. The bromine and iodine are determined in different aliquots after oxidation to halate. Furthermore individual halogens can be determined by this method. The proposed method is simple, rapid, and highly reproducible.

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Zusammenfassung Ein Verfahren zur gleichzeitigen Bestimmung von Chlor, Brom und Jod nach Zerstörung der organischen Substanz im Verbrennungskolben wurde beschrieben. Natriumborhydrid dient als Reduktionsmittel in der Absorptionslösung. Die Summe der Halogene wird mit 0,01-n Quecksilberperchlorat in einem Teil dieser Lösung titriert. Brom und Jod werden in weiteren Teilen nach ihrer Oxydation zu Halogenat bestimmt. Außerdem kann jedes Halogen für sich nach diesem gut reproduzierbaren Verfahren bestimmt werden.

     

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.

     

Simultaneous direct microdetermination of chlorine,bromine and iodine in organic compounds

Summary A new method for the separate microdetermination of chlorine, bromine and iodine present together in an organic compound is described. A 3–5 mg sample is burnt in an oxygen flask and the products are absorbed in an alkaline solution of hydrazine. Iodide with dichromate and then bromide with permanganate are oxidized to free halogen which is removed, absorbed in alkaline solution of hydrazine and reduced again to halide, while chloride remains in the original solution. The separated halides are then titrated potentiometrically with 0.01N AgNO₃ by using a sulfide ion-selective indicator electrode and a double-junction reference electrode. Accurate results within ±0.27% are obtained in the separate determination of iodine, bromine and chlorine; the corresponding standard deviations are 0.138, 0.144 and 0.159%, resp. Without weighing the sample, determination of the atomic ratios IBrCl in organic compounds is also possible. Of course, this method can be applied to the analysis of halide mixtures.

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Gleichzeitige direkte Mikrobestimmung von Chlor, Brom und Jod in organischen Verbindungen

Zusammenfassung Eine neue Methode zur Mikrobestimmung von Chlor, Brom und Jod nebeneinander in organischen Verbindungen wurde beschrieben. Die Einwaage (3–5 mg) wird in einem Sauerstoffkolben verbrannt. Die Produkte werden in alkalischer Hydrazinlösung absorbiert. Jodid und dann Bromid werden mit Bichromat bzw. Permanganat oxydiert und die entsprechenden freien Halogene entfernt, in alkalischer Hydrazinlösung absorbiert und wieder zu Halogenid reduziert, während Chlorid in der ursprünglichen Lösung verbleibt. Die einzelnen Halogenide werden dann potentiometrisch mit 0,01N AgNO₃ unter Verwendung einer suifidionenselektiven Indikatorelektrode und einer Double-junction-Referenzelektrode titriert. Resultate innerhalb ±0,27% werden bei der Bestimmung von Jod, Brom und Chlor erhalten; die entsprechenden Standardabweichungen sind 0,138, 0,144 bzw. 0,159%. Bei der Analyse einer ungewogenen Substanzmenge ist die Bestimmung der Atomverhältnisse JBrCl in organischen Verbindungen ebenfalls möglich. Diese Methode ist selbstverständlich auf die Analyse von Halogenidgemischen anwendbar.

     

Simultaneous determination of microgram amounts of chlorine or bromine or iodine and sulfur in organic compounds

A general method for the simultaneous and rapid determination of microgram amounts of chlorine or bromine or iodine and sulfur in organic compounds is described.The procedure is based on the combustion of the sample, containing approximately 0.005 meq of Cl or Br or I and 0.005 meq of S. by the Schöniger flask technique, using potassium hydroxide and hydrazine hydrate as absorption solution. The excess of hydrazine is eliminated with hydrogen peroxide after combustion.This method allows complete reduction of halogens to halides and oxidation of sulfur to sulfate.The halide ions are titrated with mercuric perchlorate and diphenylcarbazone as indicator; the sulfate ions with barium perchlorate and dimethylsulfonazo(III) as indicator.The results obtained are in good agreement with calculated values.     

The formation of charge-transfer complexes from N-vinylindole and chlorine,bromine, and iodine

The reaction of vinylindole with bromine, chlorine, and iodine in CCl₄ solution in the cold leads to the formation of charge-transfer complexes (CTC). The formation of CTC has been confirmed by a study of the physicochemical properties and the IR and UV spectra of the reaction products.     

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.     

A bromide-selective electrode-redox electrode cell for the potentiometric determination of bromine and free residual chlorine

A potentiometric cell consisting of a bromide-selective electrode and a platinum redox electrode is sensitive to free residual chlorine (FRC) when the sample solution is treated before measurement with reagents to give pH 5 and a bromide content of 0.1M. The calibration graph of e.m.f. vs. log [FRC] is linear over the [FRC] range from about 0.05 to 50 mg l . (the highest level tested). Not all forms of bromide-selective electrode prove suitable, but one with a silver bromide single-crystal membrane has been found to give a theoretical calibration slope, whereas one with an Ag(3)SBr compressed pellet membrane gave a sub-Nernstian response. The response to combined residual chlorine (CRC) is negligible but if both FRC and CRC are present, the sample treatment is likely to cause a reduction in FRC concentration. Tests have shown that a similar bias can be found with the commonly used DPD colorimetric method.     

A novel online approach to the determination of isotopic ratios for organically bound chlorine, bromine and sulphur

A novel approach for the measurement of (37)Cl, (81)Br and (34)S in organic compounds containing chlorine, bromine, and sulphur is presented to overcome some of the major drawbacks of existing methods. Contemporary methods either require reference materials with the exact molecular compositions of the substances to be tested, or necessitate several laborious offline procedures prior to isotope analysis. In our online setup, organic compounds are separated by gas chromatography (GC) coupled to a high-temperature reactor. Using hydrogen as a makeup gas, the reactor achieves quantitative conversion of chlorinated, brominated and sulphurated organic compounds into gaseous hydrogen chloride (HCl), hydrogen bromide (HBr), and hydrogen sulphide (H(2)S), respectively. In this study, the GC interface was coupled to a quadrupole mass spectrometer operated in single-ion mode. The ion traces of either H(35)Cl (m/z 36) and H(37)Cl (m/z 38), H(79)Br (m/z 80) and H(81)Br (m/z 82), or H(2)(32)S (m/z 34) and H(2)(34)S (m/z 36), were recorded to determine the isotopic ratios of chlorine, bromine, and sulphur isotopes. The conversion interface presented here provides a basis for a novel method for compound-specific isotope analysis of halogenated and sulphur-containing compounds. Rapid online measurements of organic chlorine-, bromine- and sulphur-containing mixtures will facilitate the isotopic analysis of compounds containing these elements, and broaden their usage in fields of environmental forensics employing isotopic concepts.     

Computerized technique in organic microelemental analysis: Part IV: Automated determination of chlorine,bromine, and iodine in organic compounds

The automatic and computerized rapid microanalytical determination of chlorine, bromine, and iodine in organic and organometallic compounds is described. The method consists of combustion of the compound in a large diameter empty tube connected to a titration vessel. The combustion products are transferred from the end of the combustion tube to the titration vessel by means of an automatic reductive SO₂-containing wash. Automatic potentiometric titration with AgClO₄ to the preset endpoint potential, using a combination silver microelectrode, serves as the endpoint detection of the titration of halides. The entire analysis, including automatic preparation of the equipment for the next determination, is programmed in a 6-min cycle. The method is blank-free; the results are accurate. Standard deviations amount to: 0.05, 0.14, and 0.18% absolute for Cl, Br, and I, respectively.The analyzer is interfaced to a real-time, time-sharing computer along with electronic microbalances and other analyzers, as part of the microanalytical laboratory computer service. The results of the analyses are reported on CR-terminals and are stored on magnetic disk for further processing.     

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.     

Determination of fluorine, chlorine, bromine and iodine by barrier discharge radiofrequency helium plasma.

A determination method of fluorine (F), chlorine (Cl), bromine (Br) and iodine (I) by a barrier discharge radiofrequency helium plasma-atomic emission spectroscopy was developed. A borosilicate glass was wrapped by two copper film electrodes, one of which was earthed, and the other was supplied with a radiofrequency high voltage (98 kHz, 3.2 kV), resulting in a discharge inside of the tube. An optical emission from the discharge tube was introduced to a charge-coupled device (CCD)-spectrometer through an optical fiber, and was monitored in the wavelength range of 730-960 nm. The emission lines of F (733.2 nm, 739.9 nm), Cl (833.3 nm, 837.6 nm, 858.6 nm, 894.8 nm, 912.1 nm, etc.), Br (827.2 nm, 882.5 nm, 889.8 nm, 926.5 nm, etc.) and I (905.8 nm) were observed. The linearity of the calibration was determined for F and Cl over the range of 1-10 microg, and for Br of 0.1-1 microg. The relative emission intensity was in the order of Br > I > Cl >F.