A rapid solvent extraction method for the determination of radio-iodine in sea water.

A solvent extraction procedure for the determination of radio-iodine in sea water is described. The water is treated with alkaline permanganate to remove algae, and, after removal of permanganate, the iodide is oxidized to iodine for extraction into toluene. The radio-iodine with carrier is stripped from the solvent then re-extracted into a smaller volume of toluene for liquid scintillation counting and colorimetric determination of carrier recovery as iodine. 2-Methyl-1-butene is used to decolorize the toluene-iodine solution under u.v. light and avoid colour quenching during counting. Samples spiked with iodine-131 showed essentially quantitative recovery from 1.0 l of sea water with a typical recovery of 80–85% of carrier. The method is applicable in the presence of high concentrations of many foreign ions and the decontamination factor for a number of radionuclides is greater than 10³. The limit of detection is less than 5.0 · 10^-9 μCi ml^-1.     

New colorimetric method for the determination of nystatin

A new colorimetric method for the determination of nystatin is reported, based on the reaction of the alkaline hydrolysis product of nystatin with p-aminoacetophenone in presence of concentrated hydrochloric acid. The proposed method determines 0.2-1.0mg of nystatin with recovery of 100.7 +/- 1.2%. The method is adopted to the determination of nystatin in pharmaceutical preparations, and interference due to the presence of sugar is eliminated.     

New reagents for determination of thorium

Summary O-, m- and p-hydroxy, 3-methoxy, 4-hydroxy, p-methoxy and 3,4-dimethoxy derivatives of cinnamic acid have been investigated for the separation and precipitation of thorium either when present alone or along with trivalent rare-earths. Except for somewhat low results with o-Coumaric acid at low concentration of thorium, all of these acids are satisfactory. However, from the point of speed and expediency, p-hydroxy cinnamic acid (p-coumaric acid) gives a granular precipitate and is to be recommended. Methoxy derivatives of cinnamic acid readily reduce Ce^IV to Ce^III state and therefore offer an advantage when precipitation of thorium is required to be carried out in presence of quadrivalent cerium.     

New luminescent terbium complex for the determination of DNA

New terbium complexes of derivatives of 2-oxo-4-hydroxy-quinoline-3-carboxylic acid are reported, which are highly luminescent, water soluble and do not require luminescence enhancers. The triplet-state energy levels of the ligands, the relative quantum yields (QYs) and the excitation maxima of the respective terbium chelates were determined. The large luminescence enhancement of one of these complexes by nucleic acids was investigated and a mechanism of its interaction with DNA is proposed. The optimal conditions for determination of DNA are equal concentrations of Tb(3+) and ligand R(1) (C = 1 x 10(-6) M), pH 9.0. Under optimal conditions the luminescence intensity (RI) is proportional to the concentration of fish sperm DNA (fsDNA) or calf thymus DNA (ctDNA), respectively, within the range of 0.05-1.5 microg ml(-1). The detection limits were 10 ng ml(-1) for fsDNA and 12 ng ml(-1) for ctDNA.     

New spectrophotometric method for the determination of phenolic hormones

A new simple, selective and accurate spectrophotometric method is described for the determination of mono- and dihydric phenolic hormones (oestrogens and catecholamines) by nitration at 50 degrees and 100 degrees , respectively, for 10 min, followed by treatment with alkali. Coloured products with absorption maxima at 430, 385, 430, 380 and 380 nm, linearly proportional to the concentration of oestrone, oestradiol, ethinyloestradiol, adrenaline and noradrenaline, respectively, are obtained. Information is presented on the effect of nitration time, temperature, solvents, and alkali concentration. The method is satisfactorily applied to the determination of these hormones in the range 10-50mug ml in the final solution, of volume 10ml. The relative standard deviation is +/- 0.5% and no interferences are caused by non-phenolic hormones.     

New spectrophotometric method for determination of cephazolin

A simple, selective and accurate spectrophotometric method has been developed for the determination of the cephalosporin-type antibiotic cephazolin. The method is based on the fast preliminary acid hydrolysis of cephazolin and the spectrophotometric determination of one of its degradation products-2-mercapto-5-methylthiadiazole.     

New turbidimetric method for determination of sulphate

Sulphate in the range (1-5) x 10(-5)M is determined by addition of 30-40 mesh lead nitrate crystals (0.2g) to 25 ml of sample solution containing 40-80% ethanol.     

New method for the determination of saturation concentration of Dichlorvos

Summary Saturation concenrtation of DDVP at room temperature (28°) has been determined by a colorimetric method. The saturation concentration at 28° are 9.39 and 8.55 mg/l for AR and technical grade samples respectively. The method consists of coupling DDVP vapours in gas-tight tubes with alkaline resorcinol at a water bath of 60–65°, when a yellow chromophore with an absorption maximum at 490 nm is formed. The linear relationship between the concentration of DDVP and absorbance at 490 nm holds good in the range of 1 to 20g DDVP. The method has been checked with a gas Chromatographie method for accuracy. These values are also verified by a physical method based on Dalton's Law of partial pressures in a gaseous mixture.

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Eine neue Methode zur Bestimmung der Sättigungskonzentration von Dichlorvos

Zusammenfassung Die Sättigungskonzentration von Dichlorvos (DDVP) bei Raumtemperatur (28° C) wurde kolorimetrisch bestimmt. Sie beträgt bei 28° C für das analytisch reine Präparat 9,39 mg/l bzw. für das technisch reine Präparat 8,55 mg/l. Das Verfahren besteht in der Kupplung von DDVP-Dampf in gasdichten Röhrchen mit alkalischem Resorcin bei Wasserbadtemperatur (60–65°), wobei eine gelbe Verbindung mit einem Absorptionsmaximum bei 490 nm gebildet wird. Die Absorption bei dieser Wellenlänge ist zwischen 1 und 20g DDVP linear. Das Verfahren wurde gaschromatographisch überprüft. Außerdem wurden die Ergebnisse auch physikalisch mittels des Gesetzes von Dalton für Partialdrucke in gasförmigen Gemischen verifiziert.

     

New methods for the determination of elements in trace amounts

Summary Recent methods for the determination of elements on trace amounts are discussed, which have been mainly developed in the author's laboratories. The review comprises the following sections: reagents and reactions, charge transfer reactions, candoluminescence, molecular emission spectroscopy in flames, enzymatic methods, gas-liquid chromatography of metal chelates, mass spectrometry of metal chelates.

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Neue Methoden zur Bestimmung von Elementen in Spurenmengen

Zusammenfassung Verfahren werden besprochen, die in den letzten Jahren hauptsächlich in den Laboratorien des Autors entwickelt wurden. Der Überblick umfaßt folgende Kapitel: Reagentien und Reaktionen, Charge-Transfer Reaktionen, Candoluminescenz, Molekular-Emissions-spektroskopie in Flammen, enzymatische Methoden, Gas-Flüssigkeits-Chromatographie von Metallchelaten und Massenspektrometrie von Metallchelaten.

Lecture presented at Euroanalysis I Conference, 28. 8.–1. 9. 1972 in Heidelberg, Germany.     

New enzymatic method for the determination of sulphite in food

Conclusions By means of the reagents used here sulphite can be measured in food samples. The determination of sulphite in food succeeds most favourably in wines, beer, juices, spices, jams, and potatoes. All samples with added sulphite showed recoveries of more than 96%.

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Neue enzymatische Methode zur Bestimmung von Sulfit in Lebensmitteln

     

New modified electrodes for the separate determination of anionic surfactants

Nylon, chitin, polyvinyl chloride, and polymethyl methacrylate molecular sieves with pores of various size are studied as membrane surface modifiers in electrodes reversible to anionic surfactants. A procedure for the synthesis of molecular sieves with pores of the specified size from water-insoluble polymeric matrix (polyvinyl chloride, polymethyl methacrylate) was developed. Different methods were proposed for modifying the electrode surface. It was demonstrated that modified electrodes provide the separate determination of alky 1 sulfates bearing alkyl radicals of different lengths (C₁₂-C₁₄).     

New analytical technique for the simultaneous determination of aromatic amines

Summary A new and sensitive analytical technique has been developed for the simultaneous determination of six aromatic amines. It is based on the differential migration of coloured derivatives formed by the reaction of the diazotized amines with 6-amino-1-naphthalene-3-sulphonic acid on a silica gel plate. The concentration is evaluated by colour comparison or by spectrophotometry under the influence of a temperature gradient. The method is highly reproducible and has been applied to the determination of amines in environmental samples. Standard deviations are 4.6–7.3%.     

New method for the spectrophotometric determination of ultramicro amounts of copper

A deep yellow colour is formed by the reaction with phenol and chloramine-T in the presence of copper, and this reaction is used for the photometric determination of copper. An aqueous solution of copper and the reagents at pH 11.5-11.6 is heated. The molar absorptivity at 410 mmu, is 2.32 x 10(6). The method has been used satisfactorily to determine ultram amounts of copper in high-purity silicon.     

New reagents for the colorimetric determination of microgram quantities of nitrite

Summary Two new reagents,N-(2-amino-phenyl) morpholine (I) andN-(2-amino-phenyl) piperidine (II), are used for determination of nitrite ion in acid solutions containing up to 20g NO₂ ^–/ml. The diazonium compound of (I) is sufficiently stable to enable measurement of absorption of light at 435 nm immediately after formation at room temperature or after standing in the dark.The reaction is sensitive to 0.05g NO₂ ^–/ml using a 1-cm light path.

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Zusammenfassung Zwei neue Reagenzien, N-(2-Aminophenyl)-morpholin (I) und N-(2-Aminophenyl)-piperidin (II) wurden für die Bestimmung des Nitritgehaltes saurer Lösungen unter 20g NO₂ ^–/ml herangezogen. Die Diazoniumverbindung von I ist hinreichend stabil zur Bestimmung der Absorption bei 435 nm unmittelbar nach ihrer Herstellung bei Zimmertemperatur oder nach Stehen im Dunkeln. Die Empfindlichkeit entspricht 0,05g NO₂ ^–/ml bei 1 cm Schichtdicke.

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Résumé On utilise deux nouveaux réactifs, la N-(amino-2 phényl) morpholine (I) et la N-(amino-2 phényl) pipéricline (II), pour doser l'ion nitrite en solutions acides contenant jusqu'à 20g NO₂ ^–/ml. Le composé diazonium de (I) est suffisamment stable pour permettre la mesure de l'absorption de la lumière à 435 nm, immédiatement après formation à la température ambiante ou après séjour à l'obscurité.La réaction est sensible à 0,05g NO₂ ^–/ml en utilisant un chemin optique de 1 cm.

     

New spectrophotometric method for the determination of trace amounts of palladium

Summary A simple, rapid, selective, and sensitive method for the spectrophotometric determination of palladium is developed based on the reaction of Pd(II) with 1-amino-4-hydroxyanthraquinone (AMHA). The reaction is carried out atpH 3.8 in 50% (v/v) ethanol-water medium. The molar absorptivity of the complexed ligand is 1.1 · 10⁴ l mol^–1 cm^–1 at 620 nm. Calibration plots are linear up to 17 µg Pd cm^–3. The optimum concentration range (Ringbom plot) is between 3–14.5 µg cm^–3. The spectral study of the reaction in solutions containing equimolar concentrations or an excess of one component, in thepH range 0.3–6.5, indicate the possible complex transitions that occur in solution. Complete graphical and logarithmic analysis of the absorbance-pH graphs was performed to demonstrate and characterize the complexation equilibria in solution. Under the optimum conditions, palladium can be determined as the noncharged complex Pd(AMHA)₂ in the presence of a large number of foreign ions. Interferences caused by zirconium(IV) could be masked with fluoride ions.

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Eine neue spektrophotometrische Methode für die Bestimmung von Palladium in Spuren

Zusammenfassung Eine einfache, schnelle und empfindliche Methode für die spektrophotometrische Bestimmung von Palladium wurde auf der Basis der Reaktion von Pd(II) mit 1-Amino-4-hydroxyanthrachinon (AMHA) entwickelt. Die Reaktion wird in 50% (v/v) Ethanol/Wasser beipH 3.8 ausgeführt. Die molare Absorption des komplexierten Liganden beträgt 1.1 · 10⁴ l mol^–1 cm^–1 bei 620 nm. Kalibrierungskurven verlaufen bis zu 17 µg Pd cm^–3 linear. Der optimale Konzentrationsbereich (Ringbom-Plot) liegt zwischen 3 und 14.5 µg cm^–3. Spektroskopische Untersuchungen der Reaktion in Lösungen, entweder mit equimolaren Konzentrationen oder mit einem Überschuß an einer Komponente impH-Bereich 0.3–6.5, lassen Rückschlüsse auf mögliche Komplex-Übergänge in Lösung zu. Es wurde eine vollständige graphische, logarithmische Analyse der Absorptions-pH-Graphen durchgeführt, um die Komplexgleichgewichte in Lösung aufzuklären und zu charakterisieren. Unter den Optimalbedingungen kann Palladium als nichtgeladener Komplex Pd(AMHA)₂ in Gegenwart einer großen Anzahl an Fremd-Ionen bestimmt werden. Schwierigkeiten mit Zirkonium(IV) konnte durch Maskierung mit Fluorid-Ionen umgangen werden.

     

New high-temperature palladium detectors for oxygen determination

Summary A new high-temperature oxygen detector is presented, which operates in repeatable cycles. In the first part of the cycle hydrogen dissolves in a bed of metallic palladium, in the second part the sample gas flows through the bed. An instantaneous temperature rise due to the heat evolved in the reaction of the oxygen contained in the sample gas with the hydrogen dissolved in the bed represents the measure of oxygen content. For this detector a general equation for the output signal has been theoretically derived and experimentally confirmed in the temperature range of 205–450°C. This equation can provide the basis for the mathematical optimization of detector operating conditions.

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Neue Hochtemperatur-Palladium-Detektoren zur SauerstoffbestimmungI. Prinzip und Signalgrundformel eines semi-kontinuierlichen Detektors

Zusammenfassung Ein neuer Hochtemperaturdetektor zur Sauerstoffbestimmung wird vorgeschlagen, dessen Wirkungsweise auf wiederholbaren Meßcyclen beruht. Im ersten Teilverlauf des Cyclus wird ein metallisches Palladiumbett mit Wasserstoff gesättigt und während des nachfolgenden Teilverlaufes wird der zu analysierende Gasstrom durch das Bett geleitet. Die Momentangröße der Temperatursteigerung, die durch Verbrennung des gelösten Wasserstoffs mit dem im Gas vorhandenen Sauerstoff verursacht wird, dient als Maß für den Sauerstoffgehalt. Die Grundformel für die Signalgröße des Sauerstoffdetektors wurde auf theoretischem Wege abgeleitet und im Temperaturbereich von 205 bis 450°C experimentell bestätigt. Die abgeleitete Gleichung kann zur mathematischen Optimierung der Arbeitsbedingungen des Detektors eingesetzt werden.

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Lecture presented at Euroanalysis V, Cracow, Poland     

New high-temperature palladium detectors for oxygen determination

Summary The results of optimization of selected operating conditions of new high-temperature palladium detectors for oxygen determination are presented. The optimization of operating conditions of the semi-continuous detector was carried out by mathematical analysis of the general equation describing the signal of the detector. The relative error of the oxygen determination, the product of the magnitude of signal and sensitivity of the detector, as well as the relative error of the determination of the magnitude of signal were analysed. The results of the optimization were employed in performance tests of the detector. In case of the continuous detector, an experimental optimization of the positions of the measuring thermocouples using a simplex optimization procedure has been performed. The simplex procedure proved to be simple and reliable. The results of the optimization allow for proper selection of the positions of the measuring thermocouples under given conditions of measurement or for selection of proper operating conditions for given positions of the thermocouples.

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Neue Hochtemperatur-Palladium-Detektoren zur SauerstoffbestimmungTeil III. Optimierung ausgewählter Arbeitsbedingungen für die Detektoren

Zusammenfassung Die Optimierung der Arbeitsbedingungen des semi-kontinuierlichen Detektors wurde durch mathematische Analyse der allgemeinen Gleichung für das Detektorsignal durchgeführt. Der relative Fehler der Sauerstoffbestimmung, das Produkt aus Signalgröße und Detektorempfindlichkeit sowie der relative Fehler der Bestimmung der Signalgröße wurden analysiert. Die Ergebnisse der Optimierung wurden bei Leistungstests des Detektors angewendet. Für den kontinuierlichen Detektor wurde eine experimentelle Optimierung der Stellung der Thermoelemente mit Hilfe eines Simplexverfahrens durchgeführt, das sich als einfach und zuverlässig erwies. Die Ergebnisse gestatten die geeignete Wahl der Stellung der Thermoelemente bei gegebenen Meßbedingungen oder die Wahl geeigneter Bedingungen für gegebene Stellung der Thermoelemente.

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Parts I and II see [1, 2]

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We also wish to thank eng. W. Wianecki for his technical assistance during the simplex optimization experiments.     

New chelating agents for colorimetric determination of calcium

Two new calcium chromoionophores2 and3 are described and their potential application to colorimetric determination of calcium is assessed. Chromogenic compound2 bears two acetic acid chelating groups and a 4-(4-nitrophenyl)azophenol chromophore. Its complexation of Ca²⁺ at pH 9.0 is accompanied by a 109-nm bathochromic shift and increase in the absorptivity. Triaryl chromoionophore3 bears two phosphonic acid chelating groups and the same azophenol chromophore. Compound3 exhibits a 107-nm bathochromic shift of the absorption maximum, an increase in the absorptivity upon complexation with Ca²⁺, and good selectivity for Ca²⁺ over Mg²⁺ at pH 7.0. Both chromoionophores exhibit linear responses from 0 to 4×10^–3 M Ca²⁺.     

New reactions for neptunium isolation and determination

The possibility of using photochemical reactions of neptunium oxidation and reduction tor analytical and preparation purposes is discussed. Results of Np isolation from alkaline solutions of heptavalent neptunium by sorption, extraction and coprecipitation are given. The colour reaction of Np(IV) with Arsenazo M is described. On this basis a spectrophotometric method of neptunium determination in the presence of a 20-fold uranium amount is suggested.     

New high-temperature palladium detectors for oxygen determination

Summary A new high-temperature detector for the continuous determination of oxygen is presented. Hydrogen diffuses at elevated temperature through a wall made of metallic palladium and reacts with oxygen contained in the analysed gas. The resultant difference between the palladium wall temperature and the ambient temperature provides the measure of the oxygen content. At a given gas-flow rate the output signal is directly proportional to the oxygen concentration. This confirms the correctness of the derived general equation for the output signal. The applicability of the detector for direct operation in hot gases has been confirmed by both laboratory experiments and industrial testing.

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Neue Hochtemperatur-Palladium-Detektoren zur SauerstoffbestimmungII. Prinzip und Untersuchung verschiedener Konstruktionsentwürfe eines kontinuierlichen Detektors

Zusammenfassung Ein neuer Hochtemperatur-Detektor zur kontinuierlichen Sauerstoffbestimmung wird vorgeschlagen. Wasserstoff diffundiert bei erhöhter Temperatur durch eine Wand aus metallischem Palladium und reagiert mit dem im zu analysierenden Gas vorhandenen Sauerstoff. Die resultierende Temperaturdifferenz zwischen der Palladiumwand und der Umgebung dient als Maß für den Sauerstoffgehalt. Bei gegebener Gasstromgeschwindigkeit ist die Signalgröße direkt proportional der Sauerstoffkonzentration, was die Richtigkeit der abgeleiteten Grundformel für die Signalgröße bestätigt. Die Anwendbarkeit des Detektors direkt im heißen Gas wurde sowohl im Labor- als auch im industriellen Maßstab bestätigt.

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Lecture partly presented at Euroanalysis V, Cracow, Poland

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Part I: see [1]