Showing papers in "Mikrochimica Acta in 1975"

Über die polarographische Bestimmung von Parathion und seinem Metabolit p-Nitrophenol in Blutextrakten

Abstract: Zur Bestimmung von Parathion und seinem Metabolit p-Nitrophenol im Blut wurde eine vereinfachte polarographische Methode vorgeschlagen. Die Trennung beider polarographisch-aktiven Substanzen wird durch selektive Extraktion mit einem Losungsmittelgemisch und ammoniakalische Ruckextraktion durchgefuhrt. Diese Isolierung gibt eine gute Ausbeute fur p-Nitrophenol (95,1-96,2%) und fur Parathion (93,1-94,5%). Die ausgearbeitete Methode last sich fur toxikologische Bestimmungen im Bereich von 20 bis 100 μg p-Nitrophenol und 40 bis 100 μg Parathion in 1 ml Blut gut verwenden.

Separation and spectrophotometric determination of trace elements in high-purity cadmium

Abstract: Die Spurenanalyse zur Bestimmung von Ag, Al, Bi, Co, Cu, Ga, Hg, In, Mn, Ni, Pb, Tl und Zn in reinstem Cadmium wurde ausgearbeitet. Nach dem vorgeschlagenen Schema werden einzelne Gruppen von Spurenelementen durch Extraktion bzw. Mitfallung getrennt und spektrophotometrisch mit Hilfe der folgenden organischen Reagenzien bestimmt: Dithizon, PAN, PAR, Rhodamin B, Brillantgrun, Chromazurol S, 1-Nitroso-2-naphthol undα-Furildioxim. Durch die Analyse einer Cadmiumprobe mit dem Zusatz bekannter Mengen der zu bestimmenden Elemente wurden Genauigkeit und Prazision der vorgeschlagenen Methode erwiesen.

Determination of traces of uranium in sea water after separation by froth flotation

Abstract: Uranium in sea water is separated by froth flotation of the uranium(VI)-Arsenazo III-Zephiramine ion-adduct and then determined by neutron activation or spectrophotometric method using the uranium(IV)-Arsenazo III complex. Results of the analysis of Pacific coastal samples by the two methods are in good agreement; an average value of 3.0μg U per liter was obtained.

Apparatus for elemental micro analysis of organic substances by frontal gas chromatography

Abstract: An automatic microanalyser for the determination of carbon, hydrogen, and nitrogen in organic compounds is described. One analysis takes about 10 min and the sample weight is 0.5–2.5 mg. Statistical analysis of the results shows the apparatus works with satisfactory precision (sC=0.2, sN=0.2, and sH=0.1% absolute). The conventional Pregl-Dumas combustion system is used under dynamic conditions with either addition of oxygen or merely an inert atmosphere. The combustion products are diluted with helium, allowed to reach diffusion equilibrium under fixed conditions, and then chromatographed by the frontal technique and detected with a katharometer.

Elektronenstrahl-Mikroanalyse von Kohlenstoffen

Abstract: Nachdem apparativ die Moglichkeit besteht, die Reihe nachweisbarer Elemente auf die 2. Periode auszudehnen, wird die quantitative Elektronenstrahl-Mikroanalyse an binaren Verbindungen des Kohlenstoffs erprobt. Von Kohlenstoff, als Reprasentant der sog. leichten Elemente, sind aus vorangegangenen Arbeiten die spektroskopischen Daten sowie die Praparationstechnik am ehesten bekannt. Die quantitativ erfaste, lokale Probenporositat sowie die unterschiedliche Form der Emissionsprofile aus den Proben und dem (Glaskohlenstoff-) Standard mussen bei den gemessenen Rontgenintensitaten Berucksichtigung finden. Mit der fur schwerere Elemente gultigen und inzwischen allgemein akzeptierten Korrekturrechnung werden die im voraus bekannten Probenkonzentrationen in theoretische Intensitatenverhaltnisse umgewandelt und mit den Meswerten verglichen. Die Metallanalysen fallen nur dann befriedigend aus, wenn in der Korrekturtheorie die Ionisationspotentiale der leichten Elemente modifiziert werden:J(C)=0,202 keV,J(O)=0,160 keV statt der niedereren, ebenfalls aus Mikrosondenmessungen ruckgerechneten Werte von Duncumb und Reed. Das bei den Kohlenstoffanalysen trotz der modifizierten Ionisationspotentiale Abweichungen auftreten, liegt in den ungenau bekannten Massenabsorptionskoeffizienten der Kohlenstoffstrahlung in den Metallen begrundet. Deshalb wurden aus den Meswerten genauere Absorptionsdaten ruckgerechnet, in deren Unsicherheit allgemein gesehen heute die eigentliche Problematik zu suchen ist.

Studies on the solvent extraction of thorium

Abstract: The solvent extraction separation of thorium with tri-n-octyl-phosphine oxide was studied Thorium was determined in gross quantities of uranium compounds using a two-cycle solvent extraction procedure in the presence of EDTA Uranium was shown to be preferentially extracted by TOPO from a 2M nitrate solution In addition, it was found that yttrium and the rare earths are extracted by TOPO Elimination of this interference was accomplished by backwashing with a fresh 2M nitrate wash solution The methods developed are rapid, selective, and sensitive for the spectrophotometric determination of thorium and yttrium The systems obey Beer's law under all concentration ranges studied, and by proper choice of final concentration and absorbance cells, the methods can be applied over wide ranges of concentration

Säulenextraktionschromatographie mit Dithizon in o-Dichlorbenzol

Abstract: Es wird uber grundsatzliche Moglichkeiten zur saulenextraktionschromatographischen Anreicherung und Trennung von Metallspuren mit Dithizon in o-Dichlorbenzol als stationare Phase auf Chromosorb W-H. P. berichtet und die jeweilige Arbeitstechnik an Beispielen demonstriert.

Dissociation of 8-hydroxyquinoline and its 5-chloro- and 5-nitro-derivatives in aqueous solutions

Abstract: The partition constants, minimal solubilities and dissociation equilibrium constants of 8-hydroxyquinoline and 5-chloro-8-hydroxy-quinoline and the partition constant of 5-nitro-8-hydroxyquinoline have been determined for the system n-octanol—aqueous buffer solution at 25° C and 0.01M ionic strength. The effect of substituent and organic solvent on these parameters have been discussed. The thermodynamic dissociation constants, obtained from spectrophotometric measurements, are: 8-hydroxyquinoline,pK1= 4.94 ± 0.01,pK2= 9.82 ± 0.01; 5-chloro-8-hydroxyquinoline,pK1 = 3.79 ± 0.01,pK2 = 9.29 ± 0.01.

Die Extraktion und Trennung von Mikromengen Silber(I) und Quecksilber(II) mit Makrocyklischen Polythioäthern

Abstract: Eine neue Trennungsmethode fur Mikromengen Silber(I) und Quecksilber(II) wurde entwickelt. Die Extraktion von Silber(I) und Quecksilber (II) aus salzsauren, perchlorsauren, pikrinsauren und salpetersauren Losungen mit 1,4,8,11-Tetrathiacyklotetradekan wurde studiert. Die Abhangigkeit der Verteilung der Metalle von der Saurekonzentration und der Ligandenkonzentration wurde festgestellt.

Spectrophotometric determination of chromium(III) using potassium hexacyanoferrate(II)

Abstract: Spectrophotometric determination of Cr(III) at 3.0- to 50-ppm range has been carried out using hexacyanoferrate(II) with a precision of 0.2%. The mean sensitivity for the complex, KCrIII [Fe(CN)5OH] is 1.86μg/ml/0.015 absorbance unit with an accuracy of 0.5% at 3-ppm level. The method has been found to be useful in the presence of a large number of ions. Interference due to some metal ions can be removed.

Multisite analysis of metabolic transients in single living cells by multichannel microfluorometry.

Abstract: A multichannel microspectrofluorometer allows the continuous monitoring of NAD(P)-linked dehydrogenases throughout the intact cell simultaneously in correlation with intracellular topography (morphological mode) or the spectral properties of NAD(P)H emission (spectral mode). Changes in NAD(P)H levels corresponding in absolute amounts to 10−15–10−16 mol can be followed with a signal-to-noise ratio over 100 to 1, following imposition of metabolic transients (e. g. with glycolytic intermediates). With glucose-6-phosphate, the level of fluorescence changes in individual cell regions imaged over separate channels may differ considerably. With glucose-1-phosphate an asynchronous response is observed, with initially a few only of the channels on which the cell is imaged, joining in the response which later on spreads throughout. The natural fluorescence of the cell shows on the spectral mode a multichannel distribution practically superposable to the emission curve of NAD(P)H crystals. Since spectral scan may be completed in 32 msec, changes in the spectral curve upon imposition of a metabolic transient can be observed down to such time resolution. Using the multichannel approach a new perspective is gained of the living cell, which suggests a certain individualization of various intracellular regions (e. g. metabolic asynchronicities, local residual glycolysis despite aerobic inhibition).

Flame photometry determination of Na, K, Li, and Ca traces in Cr-Ni steel

Abstract: A method for the determination of Li, Na, K and Ca in steel by flame photometry is described. The main components of steel (Fe, Cr, Ni and partially Mn) were electro-deposited on a mercury cathode from 1M HCl medium. Titanium and the remaining manganese were precipitated with ammonia at 60° C and a pH of 10–11. Li, Na, K and Ca were determined at 670.8, 588.9, 766.5 and 624.0 nm respectively, and the values for a blank were subtracted.

On the frequentometric estimation of the detection limit

Abstract: An outline is given of the general problems related to the operation of an analytical system with a detection function based on a two-step model. Account is taken of both the false-detection probabilityP 10 to which corresponds the detection levelyk, and the true-detection probabilityP 11. For the frequentometric estimation of the detection limit one uses the detection characteristic of an analytical system, which has two variants. In the first variant the discrimination of the analytical signal is made relative to the background signaly0, whereas in the second variant, the discrimination is made relative to the detection levelyk. An experimental example illustrates the calculation of both the detection limit and its confidence interval.

A general colorimetric procedure using oxidized chlorpromazine hydrochloride for the estimation Of enzymes dependent on NADH/NAD + and NADPH/NADP + systems

Abstract: Chlorpromazine (CPZ) hydrochloride in the presence of 20% (w/v) o-phosphoric acid is oxidised by o-iodosobenzoic acid to a stable free radical CPZ· which has an absorption maximum at 530 nm. The red coloured free radical is readily reduced to the colourless CPZ by NADH and NADPH. The reduction causes a decrease in absorbance in direct proportion to the quantity of the reduced coenzymes present. This reaction forms the basis for a general colorimetric method for the assay of NAD+- or NADP+-linked oxidoreductases. Details of the assay methods including normal values for lactic,α-hydroxybutyric, isocitric, sorbitol, glucose-6-phosphate, and 6-phosphogluconate dehydrogenases in serum and erythrocytes are given.

Alkyl ketoximes as analytical reagents. V

Abstract: The results of chloride ion concentration, acid concentration, oxime concentration and oxime steric effects in the extraction of palladium(II) chloride after reaction with 4-heptanone and 2,4-dimethyl-3-pentanone oximes, into chloroform are described. The course of the reaction is outlined.

Microestimation of phosphate in the presence of large amounts of fluoride

Abstract: A method for the microestimation of orthophosphate in the presence of large amounts of fluoride is described. A lead ion-selective electrode and a double-junction reference electrode are used to monitor the potentiometric titration with 0.01M lead perchlorate. Solutions are buffered at pH 8.25 to 8.75. A computer-controlled titration system is used for titration and data processing. Up to 400 mg of fluoride, a 13000-fold excess, can be tolerated in the estimation of 10−6 M phosphate.

Adsorption of the halogens on cerium dioxide

Abstract: CeO2, alone or mixed with La2O3, is used as halogen adsorbent in the determination of carbon and hydrogen. Quantitative data are given on the adsorption of the single halogens on various samples of pure CeO2 and La2O3. Retention of CO2 and the influence of several parameters of special interest in the carbon and hydrogen determination, have been examined. It has been found that the conditions for optimum adsorption of the halogens are a large surface and relatively low adsorption temperature. Unfortunately these conditions cannot be applied in the determination of carbon and hydrogen.

Use of polarized quinhydrone electrodes for potentiometric end-point detection in continuous coulometric titration of bases in non-aqueous media

Abstract: A potentiometric technique for monitoring coulometric titrations of small quantities of bases in 0.1M solution of sodium perchlorate in a mixture of acetic acid and acetic anhydride has been developed. In the indicating system two polarized quinhydrone electrodes are used. The titration end-point is indicated by a potential maximum due to the concentration polarization at the indicating electrodes. The effect of the following factors on the accuracy of the method has been studied: pretreatment of the indicating electrodes, magnitude of the polarization current, generation current, relative position of electrodes in the titration cell and amount of water in the system titrated. Quantities of 2.4 × 10−6–5 × 10−5 equiv of bases were titrated by the method. Errors did not exceed ±2%.

The determination of hydroxylamine in Ethiopian rivers and lakes

Abstract: Hydroxylamine has been detected and determined in a few Ethiopian rivers and lakes. It is absent in others.

Elektronenstrahl-Mikroanalyse von Kohlenstoff. V@@@Electron microprobe analysis of carbon. V: Quantitative Analyse von Carbiden

Abstract: ZusammenfassungNachdem apparativ die Möglichkeit besteht, die Reihe nachweisbarer Elemente auf die 2. Periode auszudehnen, wird die quantitative Elektronenstrahl-Mikroanalyse an binären Verbindungen des Kohlenstoffs erprobt. Von Kohlenstoff, als Repräsentant der sog. leichten Elemente, sind aus vorangegangenen Arbeiten die spektroskopischen Daten sowie die Präparationstechnik am ehesten bekannt. Die quantitativ erfaßte, lokale Probenporosität sowie die unterschiedliche Form der Emissionsprofile aus den Proben und dem (Glaskohlenstoff-) Standard müssen bei den gemessenen Röntgenintensitäten Berücksichtigung finden. Mit der für schwerere Elemente gültigen und inzwischen allgemein akzeptierten Korrekturrechnung werden die im voraus bekannten Probenkonzentrationen in theoretische Intensitätenverhältnisse umgewandelt und mit den Meßwerten verglichen. Die Metallanalysen fallen nur dann befriedigend aus, wenn in der Korrekturtheorie die Ionisationspotentiale der leichten Elemente modifiziert werden:J(C)=0,202 keV,J(O)=0,160 keV statt der niedereren, ebenfalls aus Mikrosondenmessungen rückgerechneten Werte von Duncumb und Reed. Daß bei den Kohlenstoffanalysen trotz der modifizierten Ionisationspotentiale Abweichungen auftreten, liegt in den ungenau bekannten Massenabsorptionskoeffizienten der Kohlenstoffstrahlung in den Metallen begründet. Deshalb wurden aus den Meßwerten genauere Absorptionsdaten rückgerechnet, in deren Unsicherheit allgemein gesehen heute die eigentliche Problematik zu suchen ist.SummaryOnce it is possible to analyze the elements of the second row of the periodic table quantitative electron microprobe analysis is extended to the binary compounds of carbon. For carbon which is a representative for light elements the spectroscopic data as well as the preparation technique are better known than for the other light elements. In the X-ray intensity measurement for quantitative analysis one must take into consideration the local porosity and the different X-ray profiles emitted from specimen and standard:k=k′· FE/FP.With the help of the generally accepted correction theory for heavy elements the known specimen concentrations are converted into theoretical intensity ratioskth and are compared with the measured valuesk. The metal analyses will be satisfactory if the ionisation potentialsJ of the light elements in the correction theory are modified:J(C)=0,202 keV,J(O)=0,160 keV instead of using the lower values of Duncumb and Reed, who have also obtained theseJ-values by back calculation. In the carbon analyses discrepancies betweenkth andk appear inspite of introducing the modified ionisation potentials because the mass absorption coefficients of the carbon-radiation in the metal matrix are not exactly known. Therefore from the measuredk-values better absorption data are backcalculated. To day it is the main problem to get exact absorption coefficients.

Alkyl ketoximes as analytical reagents. VIII

Abstract: A procedure is outlined for the quantitative separation ofμg amounts of palladium from gram amounts of nickel, copper or iron in hydrochloric acid or hydrochloric and sulfuric acid solutions by the chloroform extraction of the 4-heptanone oxime complex of palladium(II) chloride. Using the outlined procedure approximately 0.2% of the copper, 0.06 % of the nickel and 0.05 % of the iron taken are co-extracted.

Determination of thallium in autopsy tissues and body fluids by spectrophotometric technique.

Abstract: A sensitive and specific Spectrophotometric technique for the determination of microgram amounts of thallium in autopsy tissues and body fluids is described. The material is subjected to wet combustion, extraction of thallium as thallic chloride with ether, and finally the formation of thallium(I) dithizonate. The optimum conditions are given and the amount of thallium found in different autopsy tissues and urine recorded.

Microdetermination of ammonia using an ammonia gas-sensing electrode and a minicomputer

Abstract: The multiple addition method has been used in combination with Gran plots for the determination of 2×10−4M to 1×10−6M (28 ppm to 14 ppb) of ammonia nitrogen The ammonia was determined with an ammonia gas-sensing electrode A computer-controlled titration system was used for the titration and for dataprocessing Results within ±2% of the added amount are obtained down to ∼15×10−6M (20 ppb) of ammonia nitrogen

Anwendung des Alizarins und seiner Derivate zur Molybdänbestimmung

Abstract: Eine Methode fur die Bestimmung des Molybdans mit Alizarinkomplexon wurde entwickelt und mit anderen Alizarin-Derivaten verglichen. In Alkohol-Wasser bildet sich bei pH 5 bei Alizarinkomplexon uberschus ein Komplex im Verhaltnis 1∶1, der bei 480 nm absorbiert. Der molare Extinktionskoeffizient ist 4,689 undK f = 2,51 · 105. Die Methode wurde zur Analyse einer Stahlprobe angewendet, wobei die storenden Elemente papierchromatographisch abgetrennt wurden.

Elektrophorese und Ionenfokussierung anorganischer Ionen auf Gelen

Abstract: Im Hinblick auf grosere Auftragungsmengen wurde eine Elektrophorese anorganischer Ionen auf Polyacrylamidgel sowie auf Kieselgel beschrieben. Auf PAA-Gel wurde auch mit gewohnlicher Elektrophorese gearbeitet, auf beiden Tragern konnten mit der Methode der elektrophoretischen Ionenfokussierung einfache Trennungen von Systemen mit teils stark unterschiedlichen Mengenverhaltnissen durchgefuhrt werden.

Alkyl ketoximes as analytical reagents. VI

Abstract: A study of the chloroform extraction of the platinum(IV), rhodium(III), iridium(IV), iridium(III) and platinum(II) chlorides after reaction with 4-heptanone oxime in 1.0M hydrochloric acid solution indicates that platinum(II) constitutes a major interference in the quantitative extraction of the palladium(II) chloride-4-heptanone oxime complex. Trace amounts of platinum(IV) and rhodium(III) are extracted. Iridium(IV) and iridium(III) constitute a minor interference.