FTIR-ATR-spectroscopic analysis of Bis-Crown ether based PVC-membranes

Summary To get more information on the phase boundary and bulk membrane processes, the short and long time behaviour of potassium selective solvent polymeric membranes was studied. In parallel with the measurement of the dynamic response of model membranes, in situ spectroscopic measurements applying the Attenuated Total Reflection (ATR) technique in the infrared region, were carried out in solutions containing anions of different lipophilicity (Cl^– and SCN^–). Thin membranes (thinner than the penetration depth of IR beam) coated on the germanium reflection element by the dipping technique show no time dependence of the SCN bands in contact with KSCN solution of different concentrations, while the diffusion process of species can be monitored in thick membranes as it was shown in a time resolved study. The extremely short response times of ionophore based solvent polymeric membranes (determined under appropriate experimental conditions in this work) imply that the fundamental potential determining step of the overall response of this type of electrodes is a phase boundary process. Thus the slow inner membrane diffusion process followed by IR spectroscopy on the molecular level may affect only the long-term membrane behaviour.

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FTIR-ATR-spektroskopische Analyse von Bis-Kronenether-PVC-MembranenIII. Spektroskopische und elektrochemische in situ-Methoden zur Untersuchung von OberflÄchen- und Bulk-Membran-Prozessen

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Part II: see [4]

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Dedicated to Prof. Dr. W. Fresenius on the occasion of his 75th birthday     

Quantitative chemical analysis on paper. I

Summary A method has been proposed for the determination of small quantities of Cl^–, SCN^– and I^– in mixtures. The method is based on the use of filter paper evenly impregnated with Ag₂CrO₄. The method permits the determination of 5 to 50g of Cl^–; 15 to 100g of I^– and 10 to 150g of SCN^– with an accuracy of 1.5%.The method may also be used for determination of SCN^– alone.

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Zusammenfassung Ein Verfahren für die Bestimmung kleiner Mengen Chlorid, Rhodanid und Jodid in deren Gemischen wird vorgeschlagen. Es beruht auf der Verwendung eines mit Silberchromat gleichmäßig imprägnierten Filtrierpapierstreifens und ermöglicht die Bestimmung von 5 bis 50g Chlorid,15 bis 100g Jodid und 10 bis 150g Rhodanid mit einer Genauigkeit von 1,5%. Das Verfahren kann auch für die Bestimmung von Rhodanid allein verwendet werden.

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Résumé On a proposé une méthode pour le dosage de petites quantités de Cl^–, SCN^–, et I^– en mélanges. La méthode est fondée sur l'emploi d'un papierfiltre uniformément imprégné d'Ag₂CrO₄. Elle permet le dosage de 5 à 50g de Cl^–, 15 à 100g d'I^– et de 10 à 150g de SON^–, à la précision de 1,5%. On peut aussi utiliser la méthode pour le dosage de SCN^– seul.

     

Titration von Sulfid mit einer sulfidionensensitiven Elektrode

Zusammenfassung Eine Methode zur potentiometrischen Titration von Sulfid mit Natriumplumbat(II)lösung an einer sulfidsensitiven Membranelektrode wird beschrieben. Sie eignet sich zur Bestimmung von 10^–4% Sulfid in Gegenwart von Cl^–, Br^–, J^–, SCN^–, SO₃ ^2–, S₂O₃ ^2–

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Titration of sulphide with a sulphide-ion sensitive electrode

A method is described for the titration of sulphide with sodium plumbate(II) solution using a sulphide-sensitive electrode. The method is suitable for the determination of 10^–4% of sulphide in the presence of Cl^–, Br^–, J^–, SCN^–, SO₃ ^2–, S₂O₃ ^2–.

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Wir danken Herrn Dr. K. Obst für wertvolle Hinweise und Diskussionen.     

Liquid-liquid partition of cobalt between trilaurylamine N-oxide and aqueous thiocyanate solutions

In an attempt to gain an understanding of factors affecting the extraction of cobalt by trilaurylamine oxide, the equilibria between HX+SCN^– (where X=NO ₃ ^– , Cl^–, SO ₄ ^2– ) and benzene solutions of trilaurylamine oxide have been studied. Cobalt is quantitatively extracted by the oxide from aqueous 0.01–1M KSCN in 0.01M concentration of the acids. The extraction mechanism and the possible compositions of the extracted species are discussed. The effect of several anions on the extraction of the element from optimal aqueous solutions are reported and separation factors for a number of metal ions are given. The solvent has a potential for the group preconcentration of toxic metal ions from dilute aqueous solutions.     

Viscosity of aqueous NH4Cl and tracer diffusion coefficients of ions,water and non-electrolytes in aqueous NH4Cl,KI, and MgCl2 at 25°C

Viscosities for aqueous NH₄Cl and tracer diffusion coefficients for²²Na⁺,³⁶Cl^–, HTO, and CH₃OH, acetone and dimethylformamide (all¹⁴C-labelled) in NH₄Cl supporting electrolyte are reported for 25°, together with tracer diffusion coefficients for²²Na⁺,³⁶Cl^–, and¹⁴CH₃OH in 1M KI, and for¹⁴CH₃OH in 1M MgCl₂. The diffusion coefficient of HTO in NH₄Cl solutions is slightly larger, for most of the concentration range investigated (0.05 to 4.5 M), than the value for pure water and is almost unaffected by the supporting electrolyte up to about 4M. Similar behavior is shown by CH₃OH, acetone and dimethylformamide in NH₄Cl solutions. Onsager limiting law behavior is approached by Cl^– at NH₄Cl concentrations in the 0.05–0.1M region but at much lower concentrations by Na⁺.     

Kinetics of partition between aqueous solutions of salts and bulk liquid membranes containing neutral carriers

The relationship between the rates of transport of alkali metal cations through a bulk chloroform liquid membrane containing polynactin or dibenzo-18-crown-6 as neutral carrier and the rates of uptake and release of cation at the interfaces between aqueous phase and membrane phase were investigated. The fluxes of cations through the membranes and cation-distribution ratios between aqueous solution and membrane were strongly dependent on the anions present. The distribution ratio increased in the following order: Cl^? < NO₃^? < SCN^? < ClO₄^?, and the flux increased in the same order as the distribution ratio, except for the fluxes of KSCN and KClO₄ with polynactin. In the case of polynactin, the flux of KSCN was comparable to that of KClO₄ in spite of the fact that KSCN was less soluble in the membrane than was KClO₄. In order to clarify the cause of this apparently contradictory behavior, the apparent rate constants of uptake and release of potassium were determined independently using an equation derived from Fick's first law of diffusion. From the rates of uptake and release, it was suggested that the overall rate of cation transport through the membrane was dependent on the rate of release rather than that of uptake.     

Indirekte Bestimmung leichter Elemente durch R?ntgenfluorescenzanalyse

Zusammenfassung Es wird über eine röntgenfluorescenzanalytisehe Methode zur quantitativen Bestimmung leichter Elemente in Mikrogramm-Mengen berichtet, die durch Verwendung eines Bezugsstandards auf eine quantitative Überführung und reproduzierbare Verteilung von Niederschlägen auf Filtern verzichten kann. Das zu bestimmende leichte Element wird zusammen mit einem Bezugsstandard, der mit der Röntgenfluorescenz gut meßbar sein muß, durch ein mit der Röntgenfluorescenz ebenfalls gut meßbares Fällungsreagens ausgefällt. Das Niederschlagsgemisch wird direkt auf dem Filter vermessen. Aus den Intensitätsverhältnissen des Fällungsreagens zum Bezugsstandard werden Eichkurven erstellt und Analysenergebnisse ermittelt. Die Methode wird an Bestimmungen von Cl^– (0,7 g–4 mg), SCN^– (6 g–1mg), CN^– (10–100 g) und P0₄ ^3– (1–10 mg) demonstriert.

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Indirect determination of light elements by X-ray fluorescence analysisI. Determination of chloride, thiocyanate, cyanide and phosphate using a dependent reference standard

Because of the coprecipitation of the light element and an heavier reference element by a suitable precipitant a quantitative transfer and a reproducible distribution of the precipitate is not needed. The precipitated mixture is measured directly on the filter. From the intensity ratios of the reagent to the reference standard calibration curves are established and results are calculated. The method is demonstrated by the determination of Cl^– (0.7 g–4 mg), SCN^– (6 g–1 mg), CN^– (10–100 g) and P0₄ ^3– (1–10 mg).

     

Determination of traces of molybdenum in sea water by combined anion-exchange — graphite furnace atomic absorption spectrometry

Summary Traces of molybdenum in sea water have been preconcentrated by anion-exchange from acidified samples in the presence of sodium azide. Molybdenum adsorbs strongly on a column of Bio-Rad AG 1 (Cl^–) and can be stripped easily by elution with 2 mol/l NH₄Cl — 2 mol/l NH₄OH solution. Molybdenum in the effluent is determined by graphite furnace atomic absorption spectrometry. The combined method allows to determine traces of molybdenum in sea water as well as non-saline water on a 100 ml sample basis. The method gives a relative standard deviation of better than 8% at a molybdenum level of 10 g 1^–1 of sea water.

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Bestimmung von Molybdänspuren in Meereswasser mit Hilfe einer Kombination von Anionenaustausch und elektrothermischer Atomabsorptionsspektrometrie

     

Donorstärken von Halogenid- und Pseudohalogenidionen

Zusammenfassung Die Komplexbildung von Vanadyl(IV)-acetylacetonat wird mit Neutraldonatoren sowie mit Halogenid- und Pseudohalogenidionen in CH₂Cl₂ und CH₃CN als Lösungsmittel spektrophotometrisch untersucht. Daraus ergibt sich folgende Reihung der Donorstärken: J^––<TMP<DMFCl^–<DMSO< <Ph ₃PO<HMPAP _y–3 ^–.

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Complex formation of vanadyl(IV) acetylacetonate with neutral donors, halide and pseudohalide ions was measured spectrophotometrically in acetonitrile and methylene chloride solutions. The following order of donor strengths was found: J^––<TMP<DMFCl^–<DMSO<Ph ₃PO< <HMPAPy–3 ^–.

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Mit 2 Abbildungen     

Quantitative chemical analysis on paper: Determination of phosphate in the presence of large quantities of other ions

Summary A rapid method has been developed for the determination of phosphate by means of filter paper impregnated with lead iodide. A sample is added to the impregnated filter paper by means of a capillary, and after irrigation to cause migration of the ions a white spot is obtained as the lead iodide is converted into the phosphate. The weight of the spot is dependent on the p_H and the quantity of phosphate present.The determination is possible in the presence of SCN^–, Cl^–, Br^–, NO₃ ^–, CO₃ ^–, I^–, IO₃ ^–, CH₃COO^–, B₄O₇ ^2–, F^–, Sb₂O₇ ^4–, K⁺, Na⁺, NH₄ ⁺, OH^–, H⁺, succinic, citric and tartaric acids. The determination is impossible in the presence of C₂O₄ ^2–, SO₄ ^2–, MoO₄ ^2–, NO₂ ^–, SO₃ ^2–, S^2–, CrO₄ ^2–, or CO₃ ^2–.The method permits the determination of 7–100g of phosphate with an accuracy of 2%.

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Zusammenfassung Ein schnelles Verfahren zur Phosphatbestimmung wird besehrieben, bei dem man sich eines mit Bleijodid imprägnierten Filterpapiers bedient. Die Probe wird mit einer Kapillare auf das Papier aufgebracht. Man erleichtert die Ionenbewegung durch geeignete Befeuchtung und erhält einen weißen Fleck infolge Umsetzung des Bleijodids in -phosphat. Das Gewicht des Fleckens hängt vom p_H und von der Phosphatmenge ab.Die Bestimmung ist möglich in Gegenwart von SCN^–, Cl^–, Br^–, NO₃ ^–, CO₃ ^–, J^–, JO₃ ^–, CH₃COO^–, B₄O₇ ^2–, F^–, Sb₂O₇ ^4–, K⁺, Na⁺, NH₄ ⁺, OH^–, H⁺, Bernsteinsäure, Zitronensäure und Weinsäure; sie ist nicht möglich bei Gegenwart von C₂O₄ ^2–, SO₄ ^2–, MoO₄ ^2–, NO₂ ^–, SO₃ ^2–, S^2–, CrO₄ ^2– oder CO₃ ^2–. 7 bis 100g Phosphat können mit einer Genauigkeit von 2% bestimmt werden.

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Résumé On a développé une méthode rapide pour le dosage des phosphates sur papier-filtre imprégné d'iodure de plomb. On dépose l'échantillon sur le papier-filtre imprégné, à l'aide d'un capillaire, et, après humidification pour provoquer la migration des ions, on obtient une tache blanche quand l'iodure de plomb est converti en phosphate. Le poids de la tache dépend du p_H et de la quantité de phosphate présent.Le dosage est possible en présence de SCN^–, Cl^–, Br^–, NO₃ ^–, CO₃ ^–, I^–, IO₃ ^–, CH₃COO^–, B₄O₇ ^2–, F^–, Sb₂O₇ ^4–, K⁺, Na⁺, NH₄ ⁺, OH^–, H⁺, et des acides succinique, citrique et tartrique. Il est impossible en présence de C₂O₄ ^2–, SO₄ ^2–, MoO₄ ^2–, NO₂ ^–, SO₃ ^2–, S^2–, CrO₄ ^2– ou CO₃ ^2–.La méthode permet le dosage de 7 à 100g de phosphate avec une précision de 2%.

     

Abtrennung von Halogeniden aus stabilen Komplexen durch reduktive Sublimation

Zusammenfassung Beim Erhitzen stabiler Komplexe, die Cl^–, Br^– und J^– als Liganden enthalten, mit (NH₄)₂-HPO₄ bilden sich die entsprechenden Ammoniumhalogenide. Sie werden durch Sublimation in einem abgeschmolzenen Rohr quantitativ von der Schmelze getrennt. Durch die reduzierenden Arbeitsbedingungen wird die Bildung flüchtiger und störender Verbindungen der Begleitsubstanzen verhindert. Die potentiometrische Bestimmung von Cl^– und J^– nebeneinander wird beschrieben (Variationskoeffizient ±1,05 Rel.-% für Cl^–, ±0,75 Rel.-% für J^–).

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Separation of halogenides from stable complexes by reducing sublimation

When stable complexes, containing Cl^–, Br^– and I^– as ligands, are heated with (NH₄)₂HPO₄ the appropriate ammonium halogenides are formed. By sublimation in a closed glas-tube they are separated from the melt. The formation of volatile or otherwise interfering compounds from the reacting substances is prohibited by the reducing conditions. The potentiometric determination of Cl^– in the presence of I^– ist described (coefficient of variation: ±1.05% rel. for Cl^–, ±0.75% rel. for I^–).

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Wir danken dem Direktor des Instituts, Herrn Prof. Dr.-Ing. E. Blasius, für die Unterstützung unserer Arbeit. Der Deutschen Forschungsgemeinschaft sind wir für die Bereitstellung von Mitteln zu Dank verpflichtet.     

Solid state structure of the hydrated potassium thiocyanate complex of benzodinaphthopyridino 21-crown-7, C37H31NO6·KSCN·H2O (1 : 1 : 1)

Single crystal X-ray analysis of the hydrated KSCN complex of benzodinaphthopyridino-21-crown-7 (1) (1 : 1 : 1) is reported. Crystals of the complex are orthorhombic,Pnma, with = 16.946(4),b = 22.298(4),c = 10.390(8) Å andD _c = 1.184 g cm^–1,Z = 4. The host macroring (1) has a mirror symmetry and exists in a so-called dentists chair conformation. The cation (K^–) is coordinated to all the six ether oxygen atoms and also weakly to the pyridine N atom. The SCN^– anion group has a statistical type of disorder with opposite orientations of S and N such that nitrogen and sulphur are coordinated to K⁺. Packing of the host molecules is in columns to form quasi channels with K⁺, SCN^–, and H₂O being located inside the stacks. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82132 (9 pages).     

Über Fluorphenyliminophosphorsäuretrichloride

Zusammenfassung Die normaleKirsanov-Reaktion von fluorsubstit. Anilinen liefert Fluorphenyliminophosphorsäuretrichloride. Die Ammonolyse dieser Verbindungen führt zu Biphosphoniumchloriden der allgemeinen Form [RNH–P(NH₂)₂]₂N⁺Cl^–. Die IR-,¹⁹F- und³¹P-NMR-Spektren werden mitgeteilt und diskutiert.

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The normalKirsanov reaction of fluor-substituted anilines yields fluorinated N-phenyl-trichlorophosphineimines, which on ammonolysis give the corresponding bis(phosphoranylidene) ammonium chlorides [RNH–P(NH₂)₂]₂N⁺Cl^–. IR-,¹⁹F- and³¹P-NMR-spectra are reported and discussed.

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Mit 1 Abbildung     

Binding constants of calcium and/or magnesium electrolytes and aggregation numbers in oil-in-water type microemulsions formed by an amphoteric surfactant

The effects of anti-symmetric electrolytes (CaCl₂, Ca(SCN)₂, MgCl₂, and/or Mg(SCN)₂) and pH on the phase behavior, the -potential, the hydrodynamic diameter and the surface charge density of an oil-inwater type (O/W-type) microemulsion formed in solutions of an amphoteric surfactant (N ,N -dimethyl-N -lauroyllysine, DMLL)/n-octane/1-pentanol/brine have been examined. The formation of the microemulsion in the presence of CaCl₂ and/or Ca(SCN)₂ is of Winsor-type with an increase in the concentration of 1-pentanol. Particularly, microemulsion is not formed by the addition of Ca(SCN)₂ in a pH region less than 2.6. The -potential and the surface charge density of the microemulsion in the presence of CaCl₂ decrease with an increase in pH and show slightly positive values in the isoelectric region (pH 5-7), while, in the presence of Ca(SCN)₂, the -potential and the surface charge density show negative values in the same region at which the net charge of DMLL molecules becomes almost zero. The hydrodynamic diameters in the presence of CaCl₂ show a maximum value around pH 2.5, whereas, in the presence of Ca(SCN)₂, the minimum value is around pH 5.5. Similar tendencies are recognized in results for the -potential, the hydrodynamic diameter and the surface charge density of the O/W-type microemulsion in the presence of MgCl₂ and Mg(SCN)₂. A new formula to estimate the binding constants (K) of Ca²⁺, Mg²⁺, Cl^–, and SCN^– to the hydrophilic groups in DMLL molecules and the adsorption density of DMLL molecules on the oil/water interface (N) in the presence of antisymmetric electrolytes has been derived.K for Ca²⁺, Mg²⁺, Cl^–, and SCN^– was found to beK _Ca=0.12M^–1,K _Mg=0.14 M^–1,K _Cl=0.0084±0.0016 M^–1, respectively.N for DMLL molecules in the presence of CaCl₂, Ca(SCN)₂, MgCl₂ and/or Mg(SCN)₂ was found to be 0.50 nm^–2, 0.38 nm^–2, 0.44 nm^–2, and 0.47 nm^–2, respectively; and the surfactant (DMLL) numbers per O/W-type microemulsion droplet change from a few hundreds to a few thousands with changing pH. The larger the hydrodynamic diameter of the O/W-type microemulsion, the greater the number of DMLL molecules adsorbed on the O/W-type microemulsion surfaces.     

Indirekte Quecksilberbestimmung mit dem Nickelsalz der Antipyrin-4-Dithiocarbonsäure

Zusammenfassung Eine indirekte, extraktionsphotometrische Methode zur Bestimmung kleiner Quecksilbermengen wurde angegeben. Sie beruht auf der Verdrängung des Nickels aus farbigen, chloroformischen Lösungen von antipyrin-4-dithiocarbonsaurem Nickel. Die Herabsetzung der Lichtabsorption solcher Lösungen bei 575 nm ist der jeweiligen Quecksilbermenge proportional. Gold, Silber, Kupfer, Quecksilber(I), Cyanid und ÄDTA verhindern die Bestimmung. Der Einfluß sonstiger Fremdionen wurde untersucht.

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Summary An indirect extraction-photometric method of determining small quantities of mercury has been worked out; it is based on the displacement of nickel from (4-DTA)₂Ni. A fall of the absorption of the color of this solution after extraction with the test specimen is measured at=575 nm. The determination is not possible in the presence of Au(III), Ag(I), Cu(I), Cu(II), Hg(I) and S₂O₃ ^2–, SO₃ ^2–, CN_– ions and Complexon III. Therefore a study was made of the influence of Tl(I), Pb(II), Cd(II), Ni(II), Co(II), Cr(III), Mn(II), Fe(II), Fe(III), Zn(II), Bi(III), Al(III), as well as of C₂O₄ ^2–, C₄H₄O₆ ^2–, Cl^–, I^–, SCN^–, SO₄ ^2–.

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Résumé On a mis au point un dosage photométrique indirect, par extraction, de petites quantités de mercure; il repose sur le déplacement du nickel du composé (4-DTA)₂Ni. On mesure la diminution de l'absorption de la coloration de cette solution après l'extraction par l'échantillon étudié à = 575 nm. La présence des ions Au-III, Ag-I, Cu-I, Cu-II, Hg-I et S₂O₃ ^2–, SO₃ ^2–, CN^–, complexone-III rend le dosage impossible. On a étudié également l'influence de Tl-I, Pb-II, Cd-II, Ni-II, Co-II, Cr-III, Mn-II, Fe-II, Fe-III, Zn-II, Bi-III, Al-III, ainsi que de C₂O₄ ^2–, C₄H₄O₆ ^2–, Cl^–, I^–, SCN^–, SO₄ ^2–.

     

Hydrolysis of cis- and trans-Diammineplatinum(II) Complexes: Hydration, Equilibrium, and Kinetics Properties

We have used a combination of ultrasound and density techniques to measure the hydration parameters, apparent molar volume, and apparent molar adiabatic compressibility, of the antitumor drug cis-dichlorodiammineplatinum(II), cis-[Pt(NH₃)₂Cl₂], and its inactive isomer trans-dichlorodiammineplatinum(II), trans-[Pt(NH₃)₂Cl₂], in 10 mM NaNO₃, pH 5.6 at 37°C. The data have been interpreted in terms of the overall hydration of each isomer, the actual hydration contribution to the adiabatic compressibility, K _h, ranges from –56.4 × 10^–4 to –20.3 × 10^–4 cm³-mol^–1-bar^–1, and the volume contribution, V _h, ranges from –16.3 to –6.4 cm³-mol^–1. The negative signs of these hydration contributions indicate that the volume and compressibility of the water immobilized by the platinum complexes is smaller than the volume and compressibility of bulk water. The V _h and K _h parameters for all platinum complexes investigated are linearly dependent on the relative amount of hydrolyzed chlorides. The values of each parameter become more negative with increasing hydrolysis, and show that the degree of hydration increases. The similar dependence of the amount of hydrolyzed chloride ligands reveals similar hydration properties for these two complexes. Thus, the symmetry of the complexes, which is of crucial importance for anticancer activity, has no influence on their hydration properties. Under our experimental conditions, the equilibrium constants for the hydrolysis of cis-[Pt(NH₃)₂Cl₂] are K ₁ = 2.52 mM and K ₂ = 0.04 mM. The equilibrium constant for the first step of hydrolysis of trans-[Pt(NH₃)₂Cl₂] is 0.03 mM, while the second chloride ligand cannot be substituted by water, even in the irreversible reaction with AgNO₃. Furthermore, continuous measurements of the ultrasonic velocity during hydrolysis permits the accurate evaluation of the pseudo-first-order rate constant k ₁ for the hydrolysis of the first chloride ligand of cis-[Pt(NH₃)₂Cl₂], which is 16±1×10^–5 s^–1.     

Determination of thiocyanate at the P. p. m. level in waters using an ion-selective electrode with liquid membrane: An automated procedure

Summary Ion-selective electrode membranes responsive to the thiocyanate ion were prepared by using ion-association extraction systems. A tetradecyldimethylbenzylammonium cation was used as the exchange site in the liquid membrane using 1,2-dichloroethane (DCE). The liquid membrane electrode exhibits a Nernstian response to the thiocyanate ion down to 10^–5 M. The selectivity of the liquid membrane depended on the extractability of the diverse anion into DCE. The order of selectivity coefficients is ClO₄ ^–>I^–>SCN^–> NO₃ ^–>Br^–>Cl^–>SO₄ ^2–. The membrane potential is independent of the pH variation over the range from pH 1 to 13. This thiocyanate ion-selective electrode with liquid membrane has been applied to an automated procedure for routine determination of thiocyanate in waters.

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Bestimmung von ppm-Mengen Thiocyanat in Gewässern mit Hilfe einer Flüssigmembran: Ein automatisches Verfahren

Zusammenfassung Membranen ionenspezifischer Elektroden zur Rhodanidbestimmung wurden durch Extraktion von Ionenassoziat-Systemen hergestellt. Tetradecyldimethylbenzylammonium-Kation wurde als Austauscherseite für die Flüssigmembran aus 1,2-Dichloräthan (DCE) verwendet. Diese zeigt eine Ansprechempfindlichkeit gegenüber Rhodanid bis 10^–5 M. Die Spezifität der Flüssigmembran hängt ab von der Extrahierbarkeit des betreffenden Anions gegenüber DCE. Die Reihenfolge der Spezifitätskoeffizienten ist folgende: ClO₄ ^–>J^–>SCN^–>NO₃ ^–>Br^–>Cl^–> SO₄ ^2–. Das Membranpotential ist vom pH zwischen 1 und 13 unabhängig. Die beschriebene Elektrode wurde für die automatische Routinebestimmung von Rhodanid in Gewässern verwendet.

     

Quantitative chemical analysis on paper: Micro-determination of copper and a mixture of copper and silver

Summary A method has been suggested for the determination of small amounts of copper and of mixtures of copper and silver using filter paper impregnated with silver chloride and sodium carbonate. The method depends on competition between copper and silver ions to form complexes with cyanide added to the paper. The area of the spot produced by conversion of AgCl into Ag(CN)₂ ^– is measured by weight, and is inversely proportional to the amount of copper present, since the Cu(CN)₄ ^3– complex is preferentially formed. The silver present is determined separately, and the amount of copper calculated.The determination is possible in the presence of Bi³⁺, C³⁺, Mn²⁺, Pb²⁺, K⁺, Na⁺, Ca²⁺, Sr²⁺, Ba²⁺, Mg²⁺, NH₄ ⁺, Al³⁺, Sn²⁺, Hg²⁺, Ag⁺, Fe²⁺, Fe³⁺, NO₃ ^–, SO₄ ^2–, CO₃ ^2–, CrO₄ ^2–, Cl^–, Br^–, and SCN^–.The determination is impossible in the presence of I^–, I₂, Zn²⁺, Cd²⁺, Hg₂ ²⁺, Co²⁺, or Ni²⁺.The method permits the determination of 4–30g of copper and 8–60g of silver with an accuracy of 2%.

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Zusammenfassung Eine Methode zur Bestimmung kleiner Kupfermengen und von Kupfer-Silber-Gemischen mit Hilfe von Filtrierpapier wird vorgeschlagen, das mit Silberchlorid und Natriumcarbonat imprägniert ist. Sie beruht auf der Konkurrenz zwischen Kupfer und Silber bei der Komplexbildung mit Cyanid, das man auf das Papier aufbringt. Das Flächenausmaß des durch Komplexierung des Silbers gebildeten Fleckens wird gravimetrisch bestimmt. Es ist umgekehrt proportional zur Menge anwesenden Kupfers, da [Cu(CN)₄]^3– bevorzugt gebildet wird. Das Silber wird getrennt bestimmt und so die Kupfermenge berechnet.Die Bestimmung ist möglich in Gegenwart von Bi³⁺, Cr³⁺, Mn²⁺, Pb²⁺, K⁺, Na⁺, Ca²⁺, Sr²⁺, Ba²⁺, Mg²⁺, NH₄ ⁺, A1³⁺, Sn²⁺, Hg²⁺, Ag⁺, Fe²⁺, Fe³⁺, NO₃ ^–, SO₄ ^2–, CO₃ ^2–, CrO₄ ^2–, Cl^–, Br^– und SCN^– und nicht möglich in Gegenwart von J^–, J₂, Zn²⁺, Cd²⁺, Hg₂ ²⁺, Co²⁺ oder Ni²⁺.4 bis 30g Kupfer sowie 8 bis 60g Silber können mit einer Genauigkeit von 2% bestimmt werden.

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Résumé On propose une méthode pour doser de petites quantités de cuivre et de mélanges de cuivre et d'argent, à l'aide de papier-filtre imprégné de chlorure d'argent et de carbonate de sodium. La méthode dépend de l'effet compétitif entre les ions cuivre et argent pour former les complexes avec le cyanure déposé sur le papier. La surface de la tache formée en transformant le chlorure d'argent en Ag(CN)₂ ^– est mesurée par pesée et est inversement proportionnelle à la quantité de cuivre présent, puisque le complexe Cu(CN)₄ ^3– se forme préférentiellement. L'argent présent est dosé séparément et la quantité de cuivre s'en déduit par calcul.Le dosage est possible en présence de Bi³⁺, Cr³⁺, Mn²⁺, Pb²⁺, K⁺, Na⁺, Ca²⁺, Sr²⁺, Ba²⁺, Mg²⁺, NH₄ ⁺, Al³⁺, Sc³⁺, Hg²⁺, Ag⁺, Fe²⁺, Fe³⁺, NO₃ ^–, SO₄ ^2–, CO₃ ^2–, CrO₄ ^2–, Cl^–, Br^– et SCN^–.Le dosage est impossible en présence de I^–, I₂ ^–, Zn²⁺, Cd²⁺, Hg²⁺, Co²⁺ ou Ni²⁺. La méthode permet le dosage de 4 à 30g de cuivre et de 8 à 60g d'argent avec une précision de 2%.

     

Structural studies of diamine complexes of cobalt(II) and nickel(II) thiocyanates and selenocyanates

Summary Complexes of the types ML₂X₂ [M = cobalt(II) or nickel(II); L = hydrazine, ethylenediamine (en) or o-phenylenediamine (opd) and X = SCN^– or SeCN^–] and NiL₂(NCS)₂MCl₂ [M = cadmium(II) or mercury(II)] have been prepared and characterised by elemental analysis, molar conductance, molecular weight determination, magnetic susceptibility, electronic and i.r. spectral measurements.