Showing papers in "Mikrochimica Acta in 1969"
TL;DR: A review of the properties of dithiocarbamates is presented in this paper, in which a comparison is made of their properties with those of mono-and dialkyldithio-carbamates.
Abstract: A review of the properties of dithiocarbamates is presented in which a comparison is made of the properties of mono- and dialkyldithiocarbamates. The various sections deal with the synthesis of dithio-carbamates, their stability in acidic and alkaline solution, their reaction with oxidising agents, their spectra, polarographic behaviour and uses, and with analytical methods for their determination.
48 citations
TL;DR: In this paper, reaction loops are used in a gas chromatographic system to help determine the chemical structure of compounds and to indicate the presence of the functional group in unknown compounds, such as alcohols, acids, aldehydes, ketones, epoxides, and other compounds.
Abstract: Reaction loops may be used in a gas Chromatographic system to help determine the chemical structure of compounds Loops that retain or detain compounds with a certain functional group “subtract” these compounds and thereby indicate the presence of the functional group in unknown compounds The performance of loops in “subtracting” alcohols, acids, aldehydes, ketones, epoxides, and a variety of other compounds was studied to amplify the usefulness of this technique A simplified version of carbon-skeleton chromatography was also shown to be useful for analysis of polar or high molecular weight compounds (C12 or higher)
31 citations
TL;DR: In this paper, a large number of Zustandsdiagramme wurden quantitativ aufgenommen, e.g., the Sulfapyridin, Sulfametin, and Sulfathiazol.
Abstract: Im zweiten Teil unserer Untersuchungen an Sulfonamiden und verwandten Verbindungen wurden etwa 70 Zweistoffsysteme mit der Kontaktmethode auf Isomorphie und Mischbarkeit gepruft. Zehn Zustandsdiagramme wurden quantitativ aufgenommen. Es zeigte sich, das Sulfapyridin und Sulfathiazol den grosten Verwandtschaftsgrad aufweisen; in diesem System konnten drei isomorphe Mischkristallreihen realisiert werden. Besonderes Interesse verdienen die beiden Systeme Sulfapyridin—Sulfametin und Sulfathiazol—Sulfametin, da sie „Pseudomolekulverbindungen“ bilden. Diese kommen durch Stabilisierung des Maximums einer von auserst instabilen Modifikationen gebildeten Mischkristallreihe nach Typ. II Roozeboom zustande und ihre Liquiduskurve gleicht einer echten Molekulverbindung.
29 citations
TL;DR: Combustion, reduction, and absorption tube packing, ladle design, and sample handling procedures have been described to assure good results for the microdetermination of carbon, hydrogen and nitrogen on a great variety of organic compounds with an automatic analyzer as discussed by the authors.
Abstract: Combustion, reduction, and absorption tube packing, ladle design, and sample handling procedures have been described to assure good results for the microdetermination of carbon, hydrogen and nitrogen on a great variety of organic compounds with an automatic analyzer.
27 citations
TL;DR: A small ozone generator useful for locating double bonds inμg amounts of organic compounds is easily constructed from an inexpensive vacuum tester and useful for micro-preparative purposes.
Abstract: A small ozone generator useful for locating double bonds inμg amounts of organic compounds is easily constructed from an inexpensive vacuum tester. The unit is also useful for micro-preparative purposes.
27 citations
TL;DR: In this article, a new method for the measurement of sulphuric acid in airborne particulates is described, in which the acid present is separated from the sample matrix by microdiffusion at 200° and the acid is absorbed in sodium hydroxide and titrated by barium perchlorate.
Abstract: A new method for the measurement of sulphuric acid in airborne particulates is described. Sulphuric acid present is separated from the sample matrix by microdiffusion at 200°. The separated sulphuric acid is absorbed in sodium hydroxide, and titrated by barium perchlorate.
22 citations
TL;DR: In this paper, a direct potentiometric technique called analate additions potentiometry has been applied to the determination of fluoride using a fluoride ion selective indicator electrode, and the analytical results are comparable to those obtained by the standard additions technique.
Abstract: A novel direct potentiometric technique called analate additions potentiometry has been applied to the determination of fluoride using a fluoride ion selective indicator electrode. As expected, the analytical results are comparable to those obtained by the standard additions technique. An error of less than 1 part in 1000 and a precision of about 0.5% was achieved. The technique should be most useful in the determination of small sample volumes which cannot be done by the standard additions method without prior dilution.
20 citations
TL;DR: A rapid and convenient method for the determination of sulfur amino acids is described and N-Bromosuccinimide is used as a direct titrant using Bordeaux Red as an indicator.
Abstract: A rapid and convenient method for the determination of sulfur amino acids is described. N-Bromosuccinimide is used as a direct titrant using Bordeaux Red as an indicator. The red color of the indicator changes to distinct yellow with a sharp end point. The error is less than ±0.5% in most cases, and in a few cases it is near ±1%. Comparison of three methods has been made: back-titration; direct method using either Crystal Violet or Bordeaux Red as indicators. Bordeaux Red proved to be the more suitable end point indicator. Aqueous solutions of N-bromosuccinimide are stable over a period of several days when kept refrigerated and protected from light.
13 citations
TL;DR: In this article, a new simple, rapid and accurate amplification micro method for fluoride determination is described, based on the reaction between the sparingly soluble calcium iodate and the fluoride ion.
Abstract: A new simple, rapid and accurate amplification micro method for fluoride determination is described. It is based on the reaction between the sparingly soluble calcium iodate and the fluoride ion. After adding isopropyl alcohol to the solution, so that its final concentration is 65%, and filtering, an equivalent amount of the iodate is obtained. The latter is titrated iodometrically resulting in a six-fold amplification of the titre. The method is reproducible over a range from 0.4–8 mg fluoride ion. The mean recovery is 99.69%, after applying a correction factor due to potassium iodate solubility.
13 citations
TL;DR: In this article, a method for the detection and spectral examination of traces of porphyrin complexes by controlled demetallation and spectrofluorometry is described, which is sensitive to quantities as low as 0.05 ng.
Abstract: A method is described for the detection and spectral examination of traces of porphyrin complexes by controlled demetallation and spectrofluorometry. By carrying out the demetallation with methanesulfonic acid in the optical cell, difficulties connected with handling losses and introduction of contamination are minimized. The method is sensitive to quantities as low as 0.05 ng.
12 citations
TL;DR: Cupric chloride-triphenylphosphine complex reacts with riboflavin in alkaline medium giving an orange color having maximum absorbance at 460–465 nm and 1μg/ml as visual limit of identification.
Abstract: Cupric chloride-triphenylphosphine complex reacts with riboflavin in alkaline medium giving an orange color having maximum absorbance at 460–465 nm and 1μg/ml as visual limit of identification. This color reaction has been utilized for the spectrophotometric determination of riboflavin from pharmaceutical preparations in minute quantities. The reaction is specific for riboflavin and does not require stringent conditions. The maximum tolerable amount of other vitamins, sugars and amino acids during determination of riboflavin is reported.
TL;DR: In this article, a 3-Thianaphthenoyltrifluoroacetone (3-THI) was proposed for the spectrophotometric determination of iron(III).
Abstract: 3-Thianaphthenoyltrifluoroacetone has been proposed for the spectrophotometric determination of iron(III). The 3∶1 complex is very stable and can be extracted from acid solution into chloroform. Beer's law is obeyed and the molar extinction coefficient is 5.0·103 at 516 nm. Relatively large amounts of cobalt, nickel and copper are tolerated. The method is simple, convenient and reproducible.
TL;DR: The Brauchbarkeit einer jodidempfindlichen Elektrode fur die direkte elektrometrische Bestimmung von Jodid- und Jodationen wurde gepruft und der Einflus storender Faktoren auf die Potentiale untersucht.
Abstract: Die Brauchbarkeit einer jodidempfindlichen Elektrode fur die direkte elektrometrische Bestimmung von Jodid- und Jodationen wurde gepruft und der Einflus storender Faktoren auf die Potentiale untersucht.
TL;DR: In this paper, a new, rapid, convenient, and accurate method for the simultaneous determination of cysteine and cystine has been developed for use in pure solutions as well as in the enzymatic system.
Abstract: A new, rapid, convenient, and accurate method for the simultaneous determination of cysteine and cystine has been developed for use in pure solutions as well as in the enzymatic system, cystine reductase. N-Bromosuccinimide is the only standard solution employed in these determinations. Cysteine was determined at pH 7 by displacement of iodine from potassium iodide with N-bromosuccinimide. The total cysteine plus cystine was determined by N-bromosuccinimide using Bordeaux Red as an indicator. A comparative study to determine cysteine using N-bromosuccinimide and potassium iodate was performed. It has been found that the values obtained with potassium iodate in the enzymatic system are relatively high. N-Bromosuccinimide gives more accurate results as shown by determining the residual amount of cystine after a particular time of incubation. When N-bromosuccinimide is used as a titrant for cysteine and/or cystine in pure solutions the error is less than ±1%. When N-bromosuccinimide is used as a titrant in the enzymatic system for the determination of cystine, the method is more precise and more accurate when compared to the use of potassium iodate.
TL;DR: In this paper, a modification of the combustion flask method of Schoniger is described, which makes possible the micro determination of chlorine or bromine in highly halogenated organic compounds.
Abstract: A description is given of a modification of the combustion flask method ofSchoniger which makes possible the microdetermination of chlorine or bromine in highly halogenated organic compounds. Sodium borohydride as a reducing agent is employed in the absorbing solution. For simplicity and rapidity in operation, the proposed method has a decided advantage over more conventional ones. It is also quite reliable.
TL;DR: In this article, an automatic spectrophotometric reaction-rate method is described for the ultramicro determination of manganese(II) based on the potassium periodate-diethylaniline reaction.
Abstract: An automatic spectrophotometric reaction-rate method is described for the ultramicrodetermination of manganese(II). The method is based on the potassium periodate-diethylaniline reaction which is catalyzed by manganese. The time required for the reaction to produce a small fixed amount of colored product is measured automatically and related directly to the manganese concentration. Maximum tolerable amounts of interfering ions were determined. Ultramicro amounts of manganese in the range 3–30 ng were determined with relative errors of about 2% and measurement times of 15–150 seconds. The coefficient of variation was 1.0%. The method was applied for the determination of manganese in natural waters.
TL;DR: A micromethod for the determination of haemoglobin in plasma is described, which utilises the peroxidase activity of haenoglobin with CPZ as H-donor, and is sensitive to 3μg ofHaemoglobin per sample.
Abstract: A micromethod for the determination of haemoglobin in plasma is described. It utilises the peroxidase activity of haemoglobin with CPZ as H-donor, and is sensitive to 3μg of haemoglobin per sample. Effects of substrates and reaction conditions are reported. The method can also be used for the quantitative and qualitative estimation of urine haem proteins.
TL;DR: In this article, C-H-Gehalt organischer stickstoffhaltiger Verbindungen kann bestimmt werden, ohne irgendein Reagens zur Absorption der Stickoxide anzuwenden.
Abstract: Der C-H-Gehalt organischer stickstoffhaltiger Verbindungen kann bestimmt werden, ohne irgendein Reagens zur Absorption der Stickoxide anzuwenden.
TL;DR: The use of liquid scintillation counting method for the determination of 14C labelled ametryne on thin-layer chromatograms has been thoroughly investigated in this article, which has a reproducibility of 1 to 2% and a detection limit of 0.005μg per spot at a 3 ∶ 1 signal to background ratio.
Abstract: SummaryThe use of the liquid scintillation counting method for the determination of14C labelled ametryne on thin-layer chromatograms has been thoroughly investigated. Aging, quenching effect of carrier and adsorbents as well as temperature stability of the compound in the adsorbed state have been studied. The method has a reproducibility of 1 to 2% and a detection limit of 0.005μg per spot at a 3 ∶ 1 signal to background ratio. Fluorescence quenching was used for the location of spots on the chromatogram. Recovery studies were carried out by this method. After 30 minutes development on a chromatoplate coated with silicagel, about 90% of the ametryne was recovered independent of solvent system used. About 75% of the ametryne was recovered from a two-dimensional chromatogram. Recoveries of ametryne from water and soil samples ranged between 78 and 88%.ZusammenfassungDie Flüssigkeits-Szintillationszählung zur Bestimmung von14C-markiertem Ametryn in Dünnschichtchromatogrammen wurde eingehend geprüft. Alterung, Löschungseffekt von Trägersubstanz und Adsorptionsmitteln, Temperaturbeständigkeit der Verbindung in adsorbiertem Zustand wurden untersucht. Die Reproduzierbarkeit beträgt 1 bis 2%, die Nachweisgrenze 0,005μg pro Tüpfel, das Signal-Hintergrund-Verhältnis 3∶1. Zur Lokalisierung der Flecken wurde die Fluoreszenzlöschung herangezogen. Die Ausbeute nach 30 Minuten Entwicklung auf Silikagelplatten war ungefähr 90% Ametryn, unabhängig vom Laufmittel. Bei zweidimensionaler Arbeitsweise wurden 75% wiedergefunden. Die Ausbeute aus Wasser- und Bodenproben lag zwischen 78 und 88%.
TL;DR: In this article, a thin-layer chromatography of Se(IV), Te(IV, V(V), and Mo(VI) as ternary mixtures has been described.
Abstract: Thin-layer chromatography of Se(IV), Te(IV), V(V), and Mo(VI) as ternary mixtures has been described. The separation was effected on a silica gel G layer by employing two different solvent systems: diethyl oxalate-HCl (60∶1v/v) andn-butyl acetate-HCl (40∶0.6v/v). The chromatograms were visualized with 0.1M potassium thiocarbonate (PTC) spray and the limits of identification as determined, lie between 1.27 and 2.04μg.
TL;DR: On decrit un cone d'absorption des vapeurs d'iode and une cellule de titrage automatique pour doser en une settle etape l'oxygene, suivant la methode deSchiutze et Unterzaucher as discussed by the authors.
Abstract: On decrit un cone d'absorption des vapeurs d'iode et une cellule de titrage automatique pour doser en une settle etape l'oxygene, suivant la methode deSchiutze et Unterzaucher. Un appareil de combustion decrit parMonar a ete utilise.
TL;DR: In this paper, a method for simultaneous micro determination of chlorine, bromine and iodine following organic decomposition by the oxygen flask procedure of Schoniger is described, which is simple, rapid, and highly reproducible.
Abstract: A method is described which allows the simultaneous microdetermination of chlorine, bromine and iodine following organic decomposition by the oxygen flask procedure ofSchoniger. 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.
TL;DR: In this paper, a mixture containing 4-(2-pyridilazo)-resorcinol and mercuric nitrate has been found to be a very sensitive reagent for hydrogen cyanide.
Abstract: Ultramicro capillary methods for testing of cyanides, thiocyanates, hexacyanoferrates(II) and (III) are proposed. Traces of any of them can be detected in the presence of the others. A mixture containing 4-(2-pyridilazo)-resorcinol and mercuric nitrate has been found to be a very sensitive reagent for hydrogen cyanide. A capillary technique is described for the azide-iodine test.
TL;DR: Two new aromatic acids, 3,4- and 3,5-dimethylhippuric acids, have been prepared by reacting acid chlorides of corresponding benzoic acids with sodium glycinate as a method of identification by thin-layer chromatography.
Abstract: Two new aromatic acids, 3,4- and 3,5-dimethylhippuric acids, have been prepared by reacting acid chlorides of corresponding benzoic acids with sodium glycinate. Their physico-chemical properties and spectroscopic patterns (ultraviolet and infrared) have been described in this report as well as a method of identification by thin-layer chromatography.
TL;DR: In this article, the separation of 13 sugars by means of 8 solvents and one-and two-dimensional chromatography on cellulose and starch layers is described, and good results were obtained on the cellulose layers.
Abstract: The separation of 13 sugars by means of 8 solvents and one- and two-dimensional chromatography on cellulose and starch layers is described. Good results were obtained on cellulose layers.
TL;DR: In this article, a modified absorption train directly connected to the combustion tube is described, where the H2O-absorption tube is reduced in diameter and the CO2-absorptions tube is provided with self-sealing valves.
Abstract: Irregularities in the carbon results in CH-determinations with the Coleman Model 33 Carbon Hydrogen Analyzer are described. These irregularities are caused by the difference between the equilibrated (true) and the apparent weight of the CO2-absorption tube. This weight difference is correlated with the amount of carbon dioxide evolved during analysis. A modified absorption train directly connected to the combustion tube is described. The H2O-absorption tube is reduced in diameter and the CO2-absorption tube is provided with self-sealing valves. The error caused by the lack of acclimatization can be offset by the use of quantities of sample yielding nearly constant amounts of carbon dioxide, and by weighing the CO2-absorption tube exactly 3 minutes after the end of the combustion cycle. With this method, accurate CH-values are obtained.
TL;DR: Very sensitive nanogram techniques for the detection of fluorine are described, based upon the evolution of hydrofluoric acid which is revealed by the Cerium(III)-Alizarin Complexone reagent.
Abstract: Very sensitive nanogram techniques for the detection of fluorine are described. They are based upon the evolution of hydrofluoric acid which is revealed by the Cerium(III)-Alizarin Complexone reagent. The methods are suitable for the detection of fluoride in waters, minerals, salts as well as in organic compounds including complex pharmaceutical preparations.
TL;DR: In this paper, a critical study has been made of the application of the rapidVeceřa cobalto-cobaltic oxide method, the rapidKorshun-Klimova straight empty tube method and the rapidBelcher-Ingram empty-tube method for the microdetermination of carbon and hydrogen in steroids.
Abstract: A critical study has been made of the application of the rapidVeceřa cobalto-cobaltic oxide method, the rapidKorshun-Klimova straight empty tube method and the rapidBelcher-Ingram empty tube method for the microdetermination of carbon and hydrogen in steroids. Simple but effective modifications have been introduced so that any of the three methods can be applied to obtain accurate results; the maximum error is ± 0.3% for a representative variety of structures.
TL;DR: Aus theoretischen Uberlegungen und experimentellen Befunden lassen sich eine Reihe von Faktoren ableiten, die bei der hochspannungselektrophoretischen Wanderung anorganischer Ionen zusammenwirken und Voraussagen uber die Wanderungsgeschwindigkeiten and Trennmoglichkeitens auserordentlich erschweren.
Abstract: Aus theoretischen Uberlegungen und experimentellen Befunden lassen sich eine Reihe von Faktoren ableiten, die bei der hochspannungselektrophoretischen Wanderung anorganischer Ionen zusammenwirken und Voraussagen uber die Wanderungsgeschwindigkeiten und Trennmoglichkeiten auserordentlich erschweren. Fur die Losung hochspannungselektrophoretischer Trennprobleme ist die Bestimmung der Wanderungswege der interessierenden Ionen in Abhangigkeit von verschiedenen Versuchsparametern (Elektrolytart, Elektrolytkonzentration, pH-Wert, Substanzmenge u. a.) zur Festlegung optimaler Trennbedingungen Voraussetzung. Infolgedessen mus auf die Einhaltung der Versuchsbedingungen (Papiersorte, Papierbefeuchtung, Feldstarke, Laufzeit u. a.) streng geachtet werden. Bei Beachtung dieser Faktoren zeichnet sich die mit modernen Geraten arbeitende Hochspannungselektrophorese durch eine hohe Reproduzierbarkeit aus und ermoglicht die rasche und exakte Trennung anorganischer Ionen im Mikrobereich.