Computerized technique in organic microelemental analysis: Part II. Automatic determination of sulfur in organic compounds

Described is the automatic and computerized rapid microanalytical determination of sulfur in organic and organometallic compounds. The procedure consists of the combustion of the compound in an empty tube, transfer of combustion products to the titration vessel by automatic wash, and, finally, colorostatic titration of sulfuric acid with Ba(ClO₄)₂ against dimethylsulfonazo III.The entire analysis and preparation of the equipment for the next determination are programmed in time of the 6-min cycle.The analyzer is interfaced to the departmental real-time time-sharing computer, along with electronic microbalances and other analyzers, as a part of the microanalytical laboratory computer service.Results of the analyses are reported on CR terminals and are also stored on the magnetic disc for further processing.     

Computerized technique in organic microelemental analysis III. Automatic determination of fluorine in organic compounds

The automatic and computerized rapid microanalytical determination of fluorine in organic and organometallic compounds is an easily reproducible procedure. The procedure consists of the combustion of the compound in an empty tube; transfer of the combustion products to the titration vessel by automatic wash; and, finally, colorostatic titration of HF with Th(ClO₄), against alizarin red S.The entire analysis and preparation of the equipment for the next determination are programmed in the time of the 6-min cycle.The analyzer is interfaced to the departmental real-time time-sharing computer, along with electronic microbalances and other analyzers, as a part of the microanalytical laboratory computer service.Results of the analyses are reported on CR terminals and are also stored on the magnetic disk for further processing.     

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 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.

     

Micro determination of chlorine or bromine in organic compounds

Summary Attention is drawn to a method recently described byCheng for the rapid micro determination of chlorine or bromine in organic compounds, which the present author feels is worthy of wide acceptance because of its rapidity, simplicity and accuracy.The organic compound is burnt in oxygen by the Schöniger flask technique, the halogen absorbed in alkaline peroxide and the resultant halide determined by titration with mercuric nitrate solution using diphenylcarbazone as indicator, the titration being carried out in an aqueous ethanol solution after adjusting the apparent pn value to 3.6.The titration procedure has been investigated with regard to the effect of p_H, and of sulphate, phosphate and fluoride ions, and means of overcoming any interference from these ions are described.

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Zusammenfassung Es wird auf die kürzlich vonCheng veröffentlichte Mikro-Schnell-bestimmungsmethode für Chlor oder Brom in organischen Verbindungen hingewiesen, die der Verfasser wegen ihrer Schnelligkeit, Einfachheit und Genauigkeit für allgemein verwendbar hält.Die organische Substanz wird nach der Flaschenmethode vonSchöniger verbrannt, das Halogen in alkalischer Peroxydlösung absorbiert und das Halogenid mit Quecksilber(II)-nitratlösung und Diphenylcarbazon als Indikator titriert. Die Titration wird in wäßriger Äthanollösung bei einem scheinbaren p_H von 3,6 ausgeführt.Der Einfluß des p_H, der Sulfat-, Phosphat- und Fluoridionen auf den Titrationsvorgang wurde untersucht und Wege zur Ausschaltung etwaiger Störungen durch diese Ionen angegeben.

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Résumé On attire l'attention sur une méthode récemment décrite parCheng, pour le microdosage rapide du chlore et du brome dans les composés organiques, et que cet auteur estime digne d'être largement utilisée en raison de sa rapidité, de sa simplicité et de sa précision.Le composé organique est brûlé dans l'oxygène suivant la technique de la fiole deSchöniger, l'halogène absorbé dans un peroxyde alcalin et l'halogénure résultant dosé par titrage avec une solution de nitrate mercurique en utilisant la diphénylcarbazone comme indicateur, le titrage étant effectué en solution hydro-alcoolique après avoir ajusté la valeur du p_H à 3,6.On a examiné le procédé de titrage en considérant l'effet du p_H et des ions sulfates, phosphates et fluorures et l'on a décrit des moyens d'éviter les interférences produites par ces ions.

     

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.     

Computerized technique in organic microelemental analysis: Determination of C,H, N,and O

A computerized on-line system for elemental analyses of C, H, N, and O is described. Four elemental analyzers and two electronic microbalances were interfaced to the computer via scanner and DVM. Calculations of percentage composition found and theoretical were collected on two teletypes. Two technicians operated the two stations. The daily output of analyses is approximately 75 CHN analyses and 25 oxygen analyses (including standards).     

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.     

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.

     

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.     

Automatic microanalyzers: IV. Automatic analyzer for rapid microdetermination of chlorine or bromine in organic compounds

An automatic microdetermination of chlorine or bromine in organic compounds is described. The sample is weighed out in an aluminum microbeaker which is dropped into a vertical combustion tube, previously described, the quartz combustion chamber of which is heated up to 1050 °C. A flash combustion in oxygen takes place and the gaseous combustion products are absorbed in a cell with a circulating absorption solution of acetic acid and hydrazine hydrate as a reducing reagent in water.Both halogens give halogenide ions in the absorption solution where they are titrated coulometrically by electrolytic silver ions with an amperometric titration end point. The precision of the results is the same as that obtained with common microanalytical techniques.     

Improvements in the microdetermination of chlorine and bromine in organic compounds

Summary Schöniger's method for the microdetermination of halogen has been improved by using ammonium hydroxide solution as an absorbing solution instead of sodium hydroxide solution in order to simplify the after treatment. On boiling the absorbing solution, interfering ions can be removed together with excess ammonia. Ammonium halide which formes in the solution is titrated with AgNO₃ solution in the presence of an adsorption indicator. Satisfactory results are obtained more rapidly.

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Zusammenfassung Um die Weiterbehandlung der Absorptionslösung bei der Mikrobestimmung der Halogene nachSchöniger zu vereinfachen, wurde an Stelle von Natronlauge Ammoniaklösung verwendet. Durch Kochen der Absorptionslösung können störende Ionen zugleich mit dem Ammoniaküberschuß entfernt werden. Das in der Lösung entstandene Ammoniumhalogenid wird mit Silbernitrat in Gegenwart eines Adsorptionsindikators titriert. Bei verkürzter Analysendauer werden zufriedenstellende Ergebnisse erzielt.

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Résumé On a amélioré la méthode deSchöniger pour le microdosage des halogénes en utilisant une solution d'ammoniaque comme absorbant à la place de la solution d'hydroxyde de sodium afin de simplifier le traitement ultérieur. En faisant bouillir la solution d'absorption on peut éliminer les ions gênants avec de l'ammoniaque en excés. On titre l'halogénure d'ammonium qui se forme en solution, par une solution d'AgNO₃ en présence d'un indicateur d'adsorption. On a obtenu des résultats satisfaisants plus rapidement.

     

Indirect polarographic microdetermination of chlorine or bromine in organic compounds

A polarographic method for the microdetermination of chlorine or bromine in organic compounds is based on oxygen-flask combustion followed by an exchange reaction of chloride or bromide with excess of solid silver chromate, and polarographic determination of the chromate liberated. The method has been applied satisfactorily to a wide range of chlorine or bromine organic compounds with a coefficient of variation not exceeding 1%.     

Microdetermination of chlorine or bromine in highly halogenated organic compounds

The microdetermination of chlorine or bromine in highly halogenated com pounds is described. The oxygen flask is used for aromatic, aliphatic and liquid sam ples with high halogen contents. A microfusion method for some of these compounds is also discussed. As many compounds as possible covering different structures were analysed. Satisfactory results were obtained.     

Iodometric microdetermination of chlorine and bromine in some highly halogenated organic compounds

Summary Highly halogenated organic compounds are combusted in a oxygen flask using water as absorbant in the case of chlorine and 0.05% hydrogen peroxide in the case of bromine. The halogenide ion formed is determined by an iodometric procedure. Results showed an average error of ± 0.1% for Cl and ± 0.2% for Br. They are in close agreement with those obtained by a mercurimetric titration. The iodometric titration is to be preferred because of simplicity and rapidity

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Jodometrische Mikrobestimmung von Chlor und Brom in einigen hochhalogenisierten organischen Verbindungen

Zusammenfassung Die Verbindung wird im Sauerstoffkolben verbrannt, wobei Wasser (Cl) bzw. 0,05%ige Wasserstoffperoxidlösung (Br) als Absorptionsmittel verwendet werden. Die gebildeten Halogenide werden jodometrisch bestimmt. Der durchschnittliche Fehler beträgt ± 0,1% (Cl) bzw. ± 0,2% (Br). Die Ergebnisse stimmen gut mit mercurimetrisch erhaltenen überein. Die jodometrische Titration ist wegen der einfachen und schnellen Durchführbarkeit vorzuziehen.