The titrimetric determination of carbon dioxide with special reference to the determination of carbon in organic compounds

The titrimetric barium carbonate method for the determination of. carbon in organic compounds has been examined and the various sources of error are discussed. The carbon dioxide from the combustion of the sample is absorbed in excess baryta containing 20% (w/v) barium chloride and the excess is back-titrated with hydrochloric acid in the presence of o-cresolphthalein indicator.The value of this method in conjunction with the previously described determination of water with succinyl chloride, for the simultaneous determination of carbon and hydrogen is assessed     

A direct titrimetric determination of barium with ethylenediaminetetra-acetate

A method is given for the titrimetric determination of barium ions with ethylencdiaininetetra-acctate, using a modified buffer solution; it is similar to the total hardness titration.     

A titrimetric method for the rapid determination of carbon in steel with an aqueous titrant

It is demonstrated that the addition of 5% of water to the non-aqueous solvent for the titrimetric determination of carbon in steel improves the performance of the titration. Modifications to the procedure are proposed which allow the normal titrant, tetra-n-butylammonium hydroxide dissolved in benzene-methanol, to be replaced by an aqueous solution of potassium hydroxide. The proposed procedure has been applied to the analysis of a wide range of standard steel samples.     

Some investigations for a titrimetric determination of nanomoles of carbon

The ultramicrocoulometric acidimetric titration of carbon dioxide in an aqueous solution was compared with a simple volumetric titration in nonaqueous solution. The lower limit of determination was about 200 and 20 ng carbon, respectively. A determination of organic carbon (as benzoic acid or sucrose) in an aqueous solution takes less than 1 min.     

Spectrophotometric and titrimetric determination of catecholamines

Ammonium metavanadate is used to determine adrenaline, noradrenaline, isopropylnoradrenaline and methyldopa by titrimetric and photometric procedures. Oxidation of these catecholamines produces aminochrome derivatives which can be measured spectrophotometrically at 485 nm. Beer's law is obeyed over the ranges 0.09-0.90 mg for adrenaline, 0.07-0.65 mg for noradrenaline, 0.07-0.75 mg for isopropylnoradrenaline and 0.10-0.95 mg for methyldopa.     

Extraction titrimetric determination of copper

Lead xanthate undergoes a quantitative, stoichiometric and fast exchange reaction with copper(II), even near the equivalence point, making it a suitable reagent for an extraction titration of copper. Many other metal ions do not participate in exchange reactions with lead xanthate. making this method selective for copper.     

A micro titrimetric dry combustion method for carbon

Summary The previously described micromethod for the titrimetric determination of carbon in organic compounds has been simplified by the introduction of a modified absorption-titration vessel. Thus the change and the steaming out of this vessel after each determination have been eliminated and the procedure was rendered more practical.Investigations as to the possibility of devising a semi-micro method along similar principles were discontinued, since it became apparent, that such a method would offer no advantages over existing gravimetric semi-micro combustion procedures.

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Zusammenfassung Die Versuche zur Vereinfachung der Titriermethode für die quantitative Bestimmung von Kohlenstoff in organischen Substanzen führten zu einer Verbesserung der Titriervorrichtung, wonach sich die jedesmalige Auswechslung und Ausdämpfung des Titriergefäßes erübrigt. Die in erster Linie als einfacher Behelf für organisch-chemische präparative Arbeiten bestimmte Methode erhält dadurch erhöhten praktischen Wert.Arbeiten zur Übertragung dieser Methode auf einen Halbmikromaßstab wurden eingestellt, da es sich zeigte, daß die Vergrößerung der Einwaage die Methode unhandlich und unpraktisch macht.

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Résumé Au cours des essais pour simplifier l'analyse titrimétrique du carbone dans les substances organiques on a introduit un vaisseau modifié pour le titrage qui permet d'épargner l'échangement et l'évaporation après chaqu'analyse. La méthode, déstinée en premier lieu à aider aux travaux organo-chimiques préparatifs reçoit ainsi une valeur pratique augmentée.Les expériences, d'élaborer cette méthode comme semi-microméthode ont été cessées, car on voyait, qu'une augmentation de la prise d'essai n'était pas favorable pour la méthode; elle la rendait moins pratique et peu maniable.

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Taken from a portion of the Thesis presented byRichard H. Nagel to the Faculty of the Graduate School, New York University, in partial fulfillment of the requirements for the degree of Master of Science. This research was carried out under the joint direction of ProfessorsR. B. Schmitt of Loyola College, Baltimore, Md., andJ. B. Niederl of New York University, New York, N. Y.     

Micro analytical determination of carbon and hydrogen

Summary Lead dioxide used for the absorption of oxides of nitrogen in a carbon and hydrogen combustion train can be very variable in quality: a practical service test for measuring the efficiency and relative capacity of batches of lead dioxide for nitrogen dioxide (under conditions similar to those present in a combustion on aPregl- type apparatus) has shown that some batches have a short life because of a correspondingly low relative capacity, whereas other batches may have a high relative capacity and give erratic values for carbon in tests on a standard substance. Investigation has shown that the relative capacity is dependent on primary particle size of the lead dioxide powder, and that material of suitable quality (with medium capacity) can be made by recommended methods.

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Zusammenfassung Das zur Absorption von Stickstoffoxyden bei der C-H-Bestimmung verwendete Bleidioxyd ist oft von sehr verschiedener Qualität. Ein geeignetes Verfahren zur Prüfung der Wirksamkeit und der relativen Aufnahmsfähigkeit von Bleidioxydproben gegenüber Stickstoffdioxyd (unter Bedingungen, wie sie in der Preglschen Verbrennungsapparatur vorherrschen) zeigte, daß manche dieser Proben infolge geringer Aufnahmsfähigkeit eine kurze Lebensdauer besitzen, während andere wiederum trotz großer relativer Aufnahmsfähigkeit falsche Kohlenstoffwerte bei der Analyse einer Standard-substanz geben. Die beschriebenen Untersuchungen zeigen, daß die relative Aufnahmsfähigkeit von der Größe der Primärteilchen des Bleidioxydpulvers abhängig ist und daß Bleidioxyd geeigneter Qualität (mit mittlerer Aufnahmsfähigkeit) mit Hilfe der vorgeschlagenen Methoden hergestellt werden kann.

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Résumé Le bioxyde de plomb utilisé pour l'absorption des oxydes de l'azote dans une grille à combustion pour carbone et hydrogène peut être de qualité très variable. Un essai en service pratique pour évaluer l'efficacité et la teneur relative de lots de bioxyde de plomb (dans des conditions similaires à celles qui se présentent dans une combustion en appareil du typePregl) a montré que quelques lots ont une durée brève à cause d'une teneur relativement basse, tandis que d'autres lots peuvent présenter une teneur relativement élevée et donner des valeurs inconstantes pour le carbone dans les essais faits sur une substance étalon. Les recherches ont montré que la teneur relative dépend d'abord de la grosseur des particules de la poudre de bioxyde et que cette matière de qualité convenable (avec une teneur moyenne) peut être fabriquée par des méthodes recommandées.

     

Rapid titrimetric determination of thorium with fluoride using SPADNS

Summary A rapid titrimetric method for the estimation of thorium in the range from 5 to 88 mg. in a 50 ml. of final volume has been developed which involves the adjustment of P_h at 3.0, addition of 2 ml. of 0.02% SPADNS indicator, dilution to volume and titration with standard NaF until the colour obtained matches a blank containing the buffered solution of the indicator alone. The method has been standardised against known amounts of thorium and a calibration curve relating the titre of the fluoride solution to thorium content has been prepared. Interferences of various cations and anions have also been studied. From the results, the quantitative nature of zirconium interference has been confirmed. The method for the determination of thorium is very rapid and the colour change being sharp from blue-violet to scarlet-red, the detection of endpoint is not at all difficult.The author wishes to thank Dr. A. K. Ghosal, Principal, Darjeeling Government College, for providing Laboratory facilities and Prof. P. Ray and Dr. A. K. Mukherjee of the Indian Association for the Cultivation of Science, Calcutta for their encouragement in the research work.     

A new method for the titrimetric determination of perchlorate

A new method for the titrimetric determination of perchlorate has been developed, based on its reduction to chloride by iron(II) in a strong sulphuric acid medium at high temperature. The effect of variables, such as the sulphuric acid concentration, the temperature and the period of heating, on the extent of reduction has been studied and the optimal conditions for analytical determination of perehlorate derived.     

A titrimetric method for the sequential determination of thorium and plutonium

A method for the sequential determination of thorium and plutonium has been developed. In the sample solution containing thorium and plutonium, thorium is first determined by complexometric titration with EDTA and then in the same solution plutonium is determined by redox titration employing potentiometry. Prior to the determination of plutonium, EDTA is destroyed by fuming with concentrated HClO₄. Thorium is determined at 10 mg level and plutonium at 1 mg level with precision and accuracy of better than ±0.5%.     

A titrimetric method for the sequential determination of thorium and uranium

A method for the sequential determination of thorium and uranium has been developed. In the sample solution containing thorium and uranium, thorium is first determined by complexometric titration with ethylenediaminetetraacetic acid (EDTA) and then in the same solution uranium is determined by redox titration employing potentiometry. As EDTA interferes in uranium determination giving positive bias, it is destroyed by fuming with HClO₄ prior to the determination of uranium. A precision and accuracy of better than ±0.15% is obtained for thorium at 10mg level and uranium ranging from 5 mg to 20 mg in the aliquot.     

The spectrophotometric and titrimetric determination of gold with ferroin as reagent

A spectrophotometric and a photometric titration method in a two-phase system for the determination of gold with ferroin is reported. Both methods are rapid and reproducible with an accuracy of ±1%. In the spectrophotometric determination Co²⁺, Cu²⁺, Ni²⁺ , Fe³⁺, Zn²⁺, Mn²⁺ and Cr³⁺ do not interfere with the determination of gold and Pt⁴⁺, Pd²⁺, Hg²⁺, Ir⁴⁺ and Os⁴⁺ can be tolerated up to a ratio of 1:1. The titrations can also be carried out in the presence of a number of diverse ions, e.g. Ni²⁺, Cu²⁺, Co²⁺, Fe³⁺, Zn²⁺, Cr³⁺, Mn²⁺, without interference; the platinum metals and Hg²⁺ cause interference but, by the use of the spectrophotometric procedure, this can be reduced.     

The small-scale titrimetric determination of complex cyanides

Summary Ferrocyanide, or ferricyanide after reduction, may be precipitated as uranyl ferrocyanide, the precipitate decomposed with alkali, and the uranium corresponding to the complex cyanide determined titrimetrically by standard methods. An alternative method, which can also be applied to cobalticyanide, is to decompose the precipitate produced with iron(II) ion, and to determine the resulting iron(III) by standard procedures. Alternatively, a known excess of iron(II) may be added, and the excess determined titrimetrically. The method may be applied to amounts of 1–100 mg of the complex ion, titrations are of the order of 1–6 ml, and relative errors over the stated range are of the order of ±2%.

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Zusammenfassung Cyanoferrat(II) oder Cyanoferrat(III), nachdem dieses reduziert wurde, lassen sich bestimmen, indem man als Uranylcyanoferrat(II) fällt, den Niederschlag mit Alkali zersetzt und die äquivalente Uranmenge nach einer Standardmethode titriert. Ein anderer Weg, der auch für die Bestimmung von Cyanokobaltat geeignet ist, führt über die Zersetzung des mit Eisen(II) erhaltenen Niederschlages und die Bestimmung des dabei entstandenen dreiwertigen Eisens nach Standardmethoden. Schließlich kann man einen gemessenen Überschuß Eisen(II) zusetzen und diesen titrieren. Das Verfahren eignet sich für 1 bis 100 mg Komplexion. Dabei werden 1 bis 6 ml Maßlösung verbraucht. Der relative Fehler beträgt ±2%.

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Résumé On peut précipiter les ferrocyanures, ou bien les ferricyanures après réduction, à l'état de ferrocyanure d'uranyle, décomposer le précipité par une base et doser par titrimétrie, au moyen de méthodes classiques, l'uranium correspondant au cyanure complexe. Une variante de la méthode, également applicable aux cobalticyanures, consiste à décomposer le précipité obtenu avec l'ion Fe-II et à doser le fer-III résultant suivant des procédés classiques. Une autre variante consiste aussi à ajouter un excès connu de fer-II et à doser l'excès par titrimétrie. On peut appliquer la méthode aux quantités de l'ordre de 1 à 100mg d'ion complexe et opérer sur 1 à 6ml environ avec des erreurs relatives de l'ordre de ±2% sur le domaine en question.

     

Simultaneous determination of carbon,hydrogen, and nitrogen

Summary It was shown that carbon, hydrogen, and nitrogen can be determined simultaneously by the pyrolytic decomposition of the organic substance in a stream of oxygen in an empty combustion tube. Carbon and hydrogen are determined in the usual way, and nitrogen is determined from the sum of the amounts present as nitrogen oxides and as elementary nitrogen.     

Simultaneous microanalytical determination of carbon,hydrogen and sulphur

Summary A microanalytical procedure for simultaneous determination of carbon, hydrogen and sulphur by combustion in a nitrogen atmosphere is described. The substance is oxidized by the thermal degradation products of silver permanganate (Körbl catalyst) which serve as a source of oxygen and as an absorbent for sulphur oxides. The carbon and hydrogen are determined by the classical methods and sulphur is converted into benzidine sulphate. The procedure is accurate, simple and quick.

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Zusammenfassung Ein mikroanalytisches Verfahren zur gleichzeitigen Bestimmung von C, H und S durch Verbrennung in Stickstoffatmosphäre wurde beschrieben. Die Substanz wird mit dem thermischen Zersetzungsprodukt von Silber-permanganat (Körbl-Katalysator) oxydiert, der als Sauerstoffdonator und als Absorbens für Schwefeloxide dient. C und H werden nach der klassischen Arbeitsweise bestimmt und S in Benzidinsulfat umgesetzt. Das Verfahren ist genau, einfach und rasch.

     

Submilligram determination of carbon,hydrogen, and nitrogen

Summary The procedure described byFrazer ^4,6 for the simultaneous determination of carbon, hydrogen, and nitrogen has been scaled down to the submilligram level with no serious loss of accuracy. Approximately six complete determinations can be made in an eight-hour day. Whereas the accuracy depends to a large extent upon the analyst's technique, the method presented is comparatively straightforward. Analysts with no previous microanalytical training have been able to obtain results equivalent to the accuracy shown in Table I after two weeks of experience with the procedure.

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Zusammenfassung Die Methode vonFrazer ^4,6 für die gleichzeitige manometrische Bestimmung von Kohlenstoff, Wasserstoff und Stickstoff wurde ohne merkliche Einbuße an Genauigkeit in den Submilligramm-Maßstab übertragen. Ungefähr sechs vollständige Bestimmungen können innerhalb 8 Stunden ausgeführt werden. Obschon die erzielbare Genauigkeit stark von der Erfahrung des Analytikers abhängt, ist das Verfahren verhältnismäßig einfach. Analytiker ohne mikrochemische Erfahrung konnten nach zweiwöchentlicher Einübung Resultate erhalten, deren Genauigkeit denen der Tabelle 1 entspricht.

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Résumé Le procédé décrit parFrazer ^4,6 pour le dosage simultané du carbone, de l'hydrogène et de l'azote a été appliqué jusqu'à l'échelle du submilligramme sans perte sérieuse de précision. On peut effectuer approximativement six déterminations complètes en une journée de travail de huit heures. Comme la précision dépend dans une large mesure de la technique de l'analyste, la méthode présentée est relativement simple.Des analystes sans entraînement préalable en microchimie ont été capables d'obtenir des résultats avec la précision montrée sur le Tableau I, après deux semaines d'essai sur ce procédé.