Determination of nitrogen by the decomposition of organic compounds with metallic potassium

Summary A micromethod was proposed for the determination of nitrogen in organic compounds, based on the fusion of organic substances with metallic potassium and subsequent complexonometric determination of the cyanide ions in the alkaline melt. The error of the method is +0.3%.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimisheskaya, No. 7, pp. 1262–1264, July, 1965     

Determination of arsenic in organic compounds

Summary Methods are described for the determination of arsenic in organic compounds. Following oxygen flask combustion using a nichrome gauze arsenic is estimated either by titration of arsenic(III) with iodine or by titration of iodine liberated from iodide by arsenic(V). An alternative colorimetric procedure involving measuring the absorbance of molybdenum blue is used following open tube digestion in the absence of halogens or sealed tube digestion in the presence of halogens.

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Bestimmung von Arsen in organischen Verbindungen

Zusammenfassung Nach Verbrennung im Sauerstoffkolben mit einem Nickeldrahtnetz als Katalysator wird das Arsen entweder durch. Titration des As(III) mit Jod oder durch Titration des durch As(V) aus Jodid ausgeschiedenen Jods bestimmt. Ein anderes Verfahren beruht auf der kolorimetrischen Bestimmung von Methylenblau nach Verbrennung im offenen Rohr bei Abwesenheit von Halogenen oder im verschlossenen Rohr bei Anwesenheit von Halogenen.

     

Ultramicrodetermination of nitrogen in organic compounds : VII. Determination of total nitrogen in dilute aqueous solution by sealed-tube method

The capillary immutability due to corrosion of glasses exposed to various solutions was studied. The analytical error of volume change caused by glass corrosion in a micro- and ultramicronitrometer was discussed. The present work has shown that the graduated tube of a decimicronitrometer made of borosilicate glass, which is used frequently in Dumas method, should be recalibrated after 1.5–2.3 months use. We therefore recommend the sealed tube method using an improved nitrometer for ultramicrodetermination of nitrogen in organic compounds.     

Study of the fate of nitrogen in organic compounds

Summary The closed-flask combustion products of some nitrogen compounds were studied. The percentage of nitrogen oxides formed (expressed as nitrate-nitrogen) was determined. Combustion of these samples, after mixing with inorganic oxidants, in a stream of oxygen was also investigated. Trials for the application of the oxygen-flask method for the microdetermination and detection of nitrogen in many organic compounds are reported.

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Zusammenfassung Die aus einigen Stickstoffverbindungen bei der Verbrennung im sauerstoffgefüllten Kolben entstehenden Produkte wurden untersucht. Der Anteil an Stickstoffoxiden (ausgedrückt als Nitratstickstoff) wurde bestimmt. Ebenso wurde auch die Verbrennung dieser Substanzen im Sauerstoffstrom bei Gegenwart anorganischer Oxydantien untersucht. Über Versuche, die Kolbenmethode zum Nachweis und zur Bestimmung des Stickstoffs in vielen organischen Verbindungen anzuwenden, wurde berichtet.

     

Determination of organic compounds in human hair

Data reported in the literature on methods for the determination of organic compounds of different classes in human hair are systematized. Special attention is given to methods for the extraction and preconcentration of organic compounds from hair. A comparative analysis of existing methods is performed.     

Determination of fluorine in organic and organometallic compounds

Summary A method is described for the determination of fluorine in organic and organo-metallic compounds. Following oxygen-filled flask combustion in a silica flask, an aliquot of the absorbent solution is analysed for fluoride by a standard addition technique utilising a fluoride selective electrode.

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Fluorbestimmung in organischen und metallorganischen Verbindungen

Zusammenfassung Nach Verbrennung im sauerstoff-gefüllten Quarzkolben wird ein gemessener Teil der Absorptionslösung nach der Standard-Zusatztechnik mit Hilfe einer fluorspezifischen Elektrode analysiert.

     

Determination of phosphorus in organic compounds by NMR

Summary A method is described for the microdetermination of phosphorus by FTNMR in organic compounds containing transition metals. Approximately 10 mg of compound is digested for the determination and 2 mg Cr added as relaxation agent.

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Zusammenfassung Eine Mikromethode zur Bestimmung des Phosphors in organischen, Übergangsmetalle enthaltenden Verbindungen mit Hilfe der Fourier-Transform P³¹ kernmagnetischen Resonanz wurde beschrieben. Ungefähr 10 mg Substanz werden mit Schwefelsäure-Perchlorsäure aufgeschlossen und 2 mg Cr^III werden als Relaxans zugegeben.

     

Determination of the solubility of organic compounds

Summary Estimations of solubility are carried out by observing with a magnifying lens the substance while it is exposed to air laden with vapor of the solvent.

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Zusammenfassung Teilchen der Substanz werden auf einem schmalen Objektträger abwechselnd einem mit dem Dampf des Lösungsmittels beladenen und einem reinen Luftstrom ausgesetzt, während sie durch ein Vergrößerungsglas beobachtet werden. Der zur Verflüssigung erforderliche Zeitraum ist offen-kundig durch den Löslichkeitsgrad bedingt.

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Résumé Une petite particule de substance placée sur une petite lame porte-objet est soumise alternativement à un courant d'air chargé de la vapeur du solvant et à un courant d'air pur tandis qu'elle est observée à l'aide d'une loupe. Le temps nécessaire à la liquéfaction dépend évidemment du degré de solubilité de la substance.

     

Determination of carbon, hydrogen and nitrogen in inorganic compounds by means of an automatic organic elemental microanalyzer

The Hewlett Packard Model 185 CHN Analyzer, which is based on an automated modified Dumas combustion technique and was designed for the analysis of organic materials, has been applied to the determination of carbon, nitrogen and hydrogen in inorganic compounds.With minor modifications to the procedure routinely used for the organic analysis, the instrument has proved to be able to broaden its original application field giving in general good performances in the inorganic domain.A particular emphasis has been put in testing nitrates, carbonates, ammonium salts and different kinds of carbon. Till now it appears that the only materials really difficult to analyze are the refractory nitrides, carbides and carbonitrides.Finally some considerations have been made in respect of the determination of the percent weight composition of mixtures through their carbon, nitrogen and hydrogen content.     

Ultramicrodetermination of nitrogen in organic compounds: Centimilligram determination of nitrogen with sealed tube method

A new improved nitrometer was developed for centimilligram determination of nitrogen by the sealed-tube method. A combustion tube having an internal volume of 1 ml was used and the sample was weighted in a boat made of copper foil, which was made by a simple device. The accurate volume of a gas granule of the blank was evaluated by observation with a micrometer microscope. A standard deviation of 0.240% was rapidly and conveniently obtained with organic compounds having a range of 5.94–66.4% nitrogen.     

Determination of carbon and hydrogen in organic fluorine compounds

A rapid determination of carbon and hydrogen in organic fluorine compounds is described. Magnesium oxide is used both as an absorbent for fluorine and as an aid to complete combustion. The time required for one determination in series is under 30 min. The method is very widely applicable.     

Determination of deuterium in organic compounds by infrared spectrophotometry

The Trenner-Arison-Walker method for the micro-analysis of deuterium in organic compounds involves oxidation of the compound with copper oxide in a sealed tube, collection of the water by vacuum distillation, and analysis of the water by infrared spectrophotometry. Experience in applying this technique to a variety of organic compounds in our laboratory has suggested a number of procedural modifications. These principally affect the methods of sample handling and water collection. Difficulties associated with temperature changes on the spectrophotometry of the deuterium-enriched water are overcome by differential analysis against natural-abundance water using a double-beam spectrophotometer.     

Physical characterization of some complexes of organic nitrogen donor compounds

The stability constants of the complexes of cyanopyridine and aminoantipyrine with some divalent transition metal chlorides were determined at different temperatures. The thermodynamic parameters were calculated; the obtained data reveal that the complexation is an endothermic process. Also it was found that the type of bonding between the ligands and the corresponding metal ion is mainly ionic in nature. The stoichiometry of the formed complexes was found to be M:L and M:2L. The structure of some prepared complexes was confirmed by IR, ¹H NMR spectra as well as elemental analysis. Thermal stability was studied using TGA technique.     

Determination of volatile organic compounds by headspace trap

A new analytical method for the determination of halogenated and aromatic volatile organic compounds in groundwater, mineral water, and drinking water at concentrations ranging between 1-10000 ng/L is developed. A new type of headspace sampler that combines static headspace sampling with a trap is used, yielding very low detection limits and good repeatability without carryover effects. An unexpected transformation of 1,1,2,2-tetrachloroethane into trichloroethene is observed and explained.     

Turbidimetric determination of nitrogen in micro and sub-micro quantities of organic compounds

Summary A turbidimetric micro and sub-micro method is proposed for the determination of organic nitrogen. The method employs sealed tube digestion of an organic compound with sulphuric acid and sodium tetraphenyl boron for the formation of turbidity which is measured for nitrogen content. The method is rapid and accurate within ± 0.3% absolute.

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Zusammenfassung Ein turbidimetrisches Mikro- und Ultramikroverfahren zur Bestimmung organisch gebundenen Stickstoffes wurde vorgeschlagen. Es beruht auf der Zerstörung der Substanz mit Schwefelsäure im verschlossenen Rohr und der Verwendung von Natriumtetraphenylborat zur Herstellung einer Trübung, deren Intensität als Maß für den Stickstoffgehalt dient. Die Methode ist rasch und innerhalb ± 0,3% genau.

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Résumé On propose une méthode turbidimétrique micro et submicro pour le dosage de l'azote organique. La méthode met en jeu la réaction en tube scellé d'un composé organique avec l'acide sulfurique et le tétraphénylborure de sodium pour la formation du trouble qui représente une mesure de la teneur en azote. La méthode est rapide et donne une précision de ± 0,3% en valeur absolue.

     

Relative energy of organic compounds II. Halides, nitrogen, and sulfur compounds

The energies of the following types of compounds are characterized by their calculated relative enthalpies: alkyl, alkenyl, and aryl halides; carboxylic acid halides; carbonyl halides; amines; carboxylic acid amides; hydrazine derivatives; nitriles; heteroaromatic compounds; nitro-compounds; organic nitrites and nitrates; organic sulfides; thiols; disulfides; sulfoxides; sulfones; organic sulfites and sulfates; and selected inorganic compounds. Stabilization energy of pyrrol and thiophene has been estimated.     

Gas-volumetric ultramicro- and microdetermination of nitrogen and other elements in organic compounds

Summary The method described byHozumi andKirsten, for the ultramicro- and microdetermination of nitrogen, based upon sealed-tube dry combustion and weighing of mercury which replaces the developed elemental nitrogen, has been modified. It has been applied to aqueous solutions, and its sensitivity has been increased considerably by carrying out the measurement of the nitrogen at reduced pressure. The principle used in measurement can also be applied to the simultaneous ultramicrodetermination of carbon, hydrogen and nitrogen, and probably also to other analytical methods where changes of gas volumes are involved.

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Zusammenfassung Das vonHozumi undKirsten beschriebene Verfahren zur Ultramikro- und Mikrobestimmung von Stickstoff wurde weiter ausgearbeitet. Es beruht auf der trockenen Verbrennung im verschlossenen Rohr und darauffolgender Auswägung jener Quecksilbermenge, die dem Volumen des elementaren Stickstoffs entspricht, der aus der Einwaage freigesetzt wurde. Die Methode wurde auf wäßrige Lösungen angewendet. Ihre Empfindlichkeit wurde erheblich gesteigert durch Messung des Stickstoffvolumens bei vermindertem Druck. Das angewandte Prinzip der Volumenbestimmung kann auch für die gleichzeitige Ultramikrobestimmung von C, H und N und wahrscheinlich auch auf andere analytische Methoden verwendet werden, bei denen Veränderungen des Gasvolumens eintreten.

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Résumé On a modifié la méthode décrite parHozumi etKirsten pour l'ultramicro et le microdosage de l'azote, fondée sur la combustion sèche en tube scellé et pesée du mercure qui remplace l'azote élémentaire dégagé. On l'a appliquée aux solutions aqueuses et l'on a considérablement augmenté sa sensibilité en effectuant la mesure de l'azote sous pression réduite. On peut aussi appliquer le principe utilisé dans la mesure à l'ultramicrodosage simultané du carbone, de l'hydrogène et de l'azote et probablement aussi à d'autres méthodes analytiques où sont mis en jeu des changements de volumes gazeux.

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Dedicated to Prof. Dr. Ing.Fritz Feigl on the occasion of his 70th birthday.