Trace uranium analysis of water from the south-west coastal region of India

Water samples collected from various sources along the south-west coastal region of India have been analyzed for trace uranium concentration. Fission track registration technique with the Dry method has been used for the analysis. Uranium concentration was found to vary from 0.28±0.01 g/l to 2.71±0.41 g/l and was higher in sea water than in well, river and tap water, respectively.     

Untersuchungen zur Bestimmung von Spurenelementen in Blutserum mit Hilfe der Totalreflexions-R?ntgenfluoreszenzanalyse

Summary The quantitative determination of trace elements in human blood serum by Total Reflection X-Ray Fluorescence Analysis (TXRF) is influenced by absorption- and reflection-effects caused by the organic (proteins) and inorganic (P, S, Na, K, Ca, Cl) matrices. To minimize these effects we have developed a sample preparation technique based on the decomposition of the organic matrix and followed by the separation of the trace elements from the organic matrix by ion-exchange. The described method enables the simultaneous determination of K (1584 g), Ca (666 g), Fe (22 g), Cu (9.6 g), Zn (8.8 g), Se (0.97 g), Sn (1.3 g), Pb (0.12 g) and Rb (1.6 g) (obtained values in parentheses).

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Herrn Prof. Dr. G. Tölg zum 60. Geburtstag gewidmet     

Nuclear interferences of uranium and thorium in a reactor neutron activation analysis determination of cerium using the radionuclides141Ce and143Ce

The interference contributions of uranium and thorium to the determination of cerium based on radionuclides¹⁴¹Ce and¹⁴³Ce produced by irradiation in a reactor core was determined. The values of the interference contributions for¹⁴¹Ce were 0.28±0.01 g Ce/g U and /2.01±0.05/x10^–3 g Ce/g Th, and for¹⁴³Ce 1.33±0.03 g Ce/g U and /9.0±0.2/x10^–3 g Ce/g Th.     

Redox Properties of Rhodium(III) Oxo-Bridged Carboxylate Complexes

Chemical and electrochemical oxidation of rhodium (III) oxo-bridged carboxylate complexes was studied. The chemical [with O₃ and Ce(IV) salts] or electrochemical (at potentials of 1.00-1.20 V) oxidations of the binuclear complexes [Rh₂(-O)(-O₂CCH₃)₂(H₂O)₆]^{2 +} and [Rh₂(-O)(-O₂CCF₃)₂(H₂O)₆]^{2 +} leads to the superoxo complexes [Rh₂(-O)(O₂-)(-O₂CCH₃)₂(H₂O)₅]⁺ and [Rh₂(-O)(O₂ ^-)(-O₂CCF₃)₂(H₂O)₅]⁺ with terminal coordination of O₂-. The trinuclear acetate [Rh₃(₃-O)(-O₂CCH₃)₆(H₂O)₃]⁺, unlike its trifluoroacetate analog [Rh3(₃-O)(-O₂CCF₃)₆(H₂O)₃]⁺, is oxidized only electrochemically at a potential of 1.38 V. The oxidation of [Rh₃(₃-O)(-O₂CCH₃)₆(H₂O)₃]⁺ is reversible and involves formation of an unstable superoxo group O₂ ^- between two Rh₃III(₃-O) cores.     

Certified reference materials (CRM 408 and 409) for quality control of main components (ammonium, calcium, hydronium, magnesium, nitrate, potassium, sodium and sulphate) in simulated rain water

Analyses of rainwater are routinely performed by a number of organisations to monitor the contribution from rainwater to the component occurrences in the environment and the acidification of the environment. To control the quality of such determinations, the Community Bureau of Reference (BCR) has organised a certification campaign to produce two simulated rainwater reference materials (CRM 408, low mineral content and CRM 409, high mineral content). The materials were carefully prepared (addition of pro analysis and supra pure reagents with the mentioned elements to silica-free deionised water) and its homogeneity and long-term stability were verified. The materials were certified for their contents of ammonium (106 mol/kg) (CRM 409), calcium (7.68 and 15.5 mol/kg), chloride (67.3 and 113 mol/kg), hydronium (16.6 and 48.0 mol/kg), magnesium (6.14 and 12.3 mol/kg), nitrate (20.1 and 78.1 mol/kg), potassium (4.25 mol/kg) (CRM 409), sodium (42.0 and 82.9 mol/kg) and sulphate (10.5 and 53.2 mol/kg). Indicative values (not certified) are given for ammonium and potassium in CRM 408. This paper presents the certification work performed, as well as the analytical work for the certification of the contents of relevant species.     

Study of the absorption spectra of the 4f electron transition of the Nd and Er complexes with 2-isobutylformyl-1,3-dione-indane in the presence of TX-100 and its analytical application

The absorption spectra of 4f electron transitions of the systems of neodymium and erbium with 2-isobutylformyl-1,3-dione-indane and TX-100 have been studied by normal and derivative spectrophotometry. Their molar absorptivities at the maximum absorption bands are about 7.2 (at 571 nm) times greater for neodymium and 13.1 (at 519 nm) times greater for erbium than those in the absence of the complexing agents. Use of second derivative spectra both eliminates the interference from other rare earths and increases the sensitivity from neodymium and erbium. Beers law is obeyed from 020 g/ml for neodymium and 025 g/ml for erbium. The relative standard deviations are 1.2% and 1.6% for 5.0 g/ml of neodymium and 8.0 g/ml of erbium, respectively. The detection limits (signal-to-noise ratio=2) are 0.14 g/ml and 0.20 g/ml. A method for the direct determination of neodymium and erbium in rare earth mixtures with good accuracy and selectivity is proposed.     

Location of chromium and nickel cations in stabilized Y zeolites

The influence of the hydrothermal treatment of stabilized and nonstabilized Y zeolites on the location of Cr and Ni cations was tested. A significant influence of the above treatment was found.

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Cr Ni. .

     

Redox Properties of Trinuclear Osmium Carbonylhydride Clusters with Unsaturated Ligands

Schemes of redox transformations were proposed for osmium carbonylhydride clusters: trinuclear (-H)Os₃(-CR = CHR')(CO)_{1 0} (R = R' = H, Ph; R = H, R' = Ph), (-H)₂Os₃(₃-L)(CO)₉ (L = C = CHPh, CHCPh), tetranuclear CpMnOs₃ (-CH = CHPh)(-H)(-CO)(CO)_{1 1}, and trinuclear Os₃(₃-C = CHPh)(CO)₉. Two-electron reduction of the trinuclear clusters results in elimination of the unsaturated ligand with preservation of the metal framework.     

Infrared and mass spectroscopic evidence for hydrocarbon formation on a supported cobalt catalyst

Interrupting the surface carbonyl development at 345 K on an aerosilsupported cobalt oxide catalyst in CO/H₂ atmosphere at maximum surface concentration of linear carbonyl species by heating to 475 K results in the formation of Fischer-Tropsch type products detectable by combined IR and MS measurements.

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345°K , , CO/H₂ , 475° -, .

     

Grenzkonzentration und Erfassungsgrenze quantitativer Analysenmethoden. Berechnung dieser Kennzahlen für (spektral-)photometrische Verfahren

Zusammenfassung Es wird vorgeschlagen, den unteren Anwendungsbereich quantitativer Methoden ebenso wie in der qualitativen Mikroanalyse durch die Begriffe Grenzkonzentration und Erfassungsgrenze zu kennzeichnen. Durch die Ableitung dieser Werte nach mathematisch-statistischen Regeln erhalten Grenzkonzentration und Erfassungsgrenze den Charakter objektiver Kennzahlen. Für photometrische und spektralphotometrische Methoden werden Gleichungen zur Berechnung der Grenzkonzentration ing/ml und in Prozent der Probe, sowie der Erfassungsgrenze ing Substanz angegeben. Berechnungsgrundlagen sind die Streuung der Blindwerte, der molare Extinktionskoeffizient oder der Sandellsche Empfindlichkeitsindex und andere analytische Parameter.

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Summary It is suggested that the lower application region of quantitative methods, just as in the case of qualitative microanalyses, be characterized by the concepts limiting concentration and detection limit. These values acquire the character of objective coefficients when they are derived in accord with mathematical-statistical laws. Equations for calculating the limiting concentration ing/ml and in % of the sample, as well as the detection limit ing of the material, are given for photometric and spectrophotometric methods. The bases for the calculation are the dispersion of the blank values, the molar extinction coefficient, or the Sandell sensitivity index and other analytical parameters.

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Herrn Professor Dr.Hans Lieb aus Anlaß seines 80. Geburtstages gewidmet.     

The spectrophotometric determination of thorium with eriochrome black T

Summary From 0.5 to 20g Th/ml may be determined with Eriochrome Black T in acetate buffered solution. Fewer ions interfere if the determination is performed in hydrochloric acid solution, but the lower limit is raised to 1g Th/ml.

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Zusammenfassung 0,5 bis 20g Th/ml können mit Eriochromschwarz T in acetatgepufferter Lösung bestimmt werden. Photometriert man in salzsaurer Lösung, so stört zwar eine geringere Zahl von Fremdionen, aber die untere Konzentrationsgrenze erhöht sich auf 1g Th/ml.

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Résumé On peut doser 0,5 à 20g Th/ml par le Noir Eriochrome T en solution tamponnée à l'acétate. Peu d'ions interfèrent si l'on réalise le dosage en solution acide chlorhydrique mais la limite inférieure se situe alors à 1g Th/ml.

     

Determination of oxygen by deuteron-induced PIPPS

Using the 871-keV¹⁶O p/1,0/ prompt -ray, oxygen was determined with a relative precision of ±3.8% at a concentration level of 120 g g^–1. The sensitivity of the method is below 10 g g^–1. 50 nm oxide layers on silicon wafers can be determined with a relative precision of 10%. A chamber for transporting targets sensitive to atmospheric gases and humidity is described.     

Determination of sulphathiazole in the presence of sulphametazine by first-derivative solid-phase spectrophotometry

Sulphathiazole in the presence of sulphametazine is determined by a method based on derivative solid-phase spectrophotometry. Both compounds are fixed on a dextran-type cation-exchange gel. The absorbance of the gel, packed in a 1-mm silica cell, is measured directly. The range of application is between 0.20 and 18.0 g/ml of sulphathiazole in the presence of up to 20 g/ml of sulphametazine, the relative standard deviation is 0.6% and the detection limit is 0.05 g/ml. The method has been applied to the determination of sulphathiazole in synthetic mixtures and pharmaceuticals, with recoveries of 95.0 to 102.5%     

Anwendung der Ringofenmethode zum Nachweis einiger Heteroelemente in organischen Verbindungen

Zusammenfassung Ein schnelles und einfaches Mikroverfahren zum Nachweis einiger Heteroatome organischer Verbindungen wurde entwickelt. Nach Aufschluß mit metallischem Kalium werden die entstehenden Ionen mit der Ringofenmethode getrennt und mit empfindlichen Reaktionen nachgewiesen. Nachweisgrenze: 0,5 bis 1g Stickstoff, 1 bis 2g Schwefel, 2 bis 3g Jod, 4 bis 5g Brom, 5 bis 10g Chlor in 0,5 bis 1 mg Einwaage.

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Summary A rapid and simple micromethod was developed for the detection of several hetero-elements in organic compounds. After breaking down the sample with metallic potassium, the resulting ions are separated by the ring oven method and detected by means of sensitive reagents. Detection limits: 0.5 to 1g nitrogen, 1 to 2g sulfur, 2 to 3g iodine, 4 to 5g bromine, 5 to 10g chlorine in samples weighing 0.5 to 1 mg.

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Résumé On a découvert un procédé à l'échelle micro, simple et rapide, pour rechercher certains hétéroéléments dans les composés organiques. Après mise en solution par le potassium métallique, on sépare les ions formés suivant la méthode du four annulaire et l'on effectue la recherche au moyen de réactions sensibles. Limite de dilution: 0,5 à 1g d'azote, 1 àg de soufre, 2 àg d'iode, 5 à 10g de chlore sur 0,5 à 1 mg de prise d'essai.

     

Preparation of μ-(η5:η5-Fulvalene)-di-μ-hydrido-bis(η5-cyclopentadienyltitanium) by the reduction of Cp2TiCl2 with LiAlH4 in aromatic solvents

Summary -(⁵:⁵-Fulvalene)-di--hydrido-bis(⁵-cyclopentadienyltitanium) (1) can be prepared by the reduction of Cp₂TiCl₂ with LiAlH₄ in methylbenzenes and in tetralin at their boiling temperatures in yields greater than 90%. The reduction proceedsvia the bis(⁵-cyclopentadienyl)titanium(III) chloride dimer which is further transformed into the unstable [Cp₂TiH] species. Thermal decomposition of the latter accompanied by hydrogen evolution gives rise to (1). -(⁵:⁵-Fulvalene)--hydrido--chloro-bis(⁵-cyclopentadienyltitanium), the first fulvalene containing compound observed in the system is formed by hydrido-chloro exchange of (1) with (Cp₂TiCl)₂ and aluminium chlorohydrides.     

Fällungsanalyse im Mikrogrammbereich: Eine neue Methode

Zusammenfassung Eine neue Methode zur Durchführung gravimetrischer Bestimmungen im Mikrogrammbereich wurde beschrieben; diese beruht im wesentlichen darauf, daß der Niederschlag nicht mehr zusammen mit dem Filter, sondern nach Überführen mit einem geeigneten Lösungsmittel in einem separaten Wägegefäß gewogen wird.Die dazu nötigen Geräte und deren Herstellung wurden beschrieben. Nach dieser Methode wurden folgende Bestimmungen mit zufriedenstellender Richtigkeit durchgeführt: 2,5–25g Al, 5–50g Cu und 5–50g Zn mit Oxin, 2,5–25g Fe(III) und 2,5–25g Ti(IV) mit N-Benzoyl-phenylhydroxylamin, 5–50g Ni und 5–50g Cu mit Salicylaldoxim, 2,5–50g Co(II) und 2,5–50g Fe(III) mit -Nitroso--naphthol sowie 5–50g Chlorid als Silberchlorid.

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Precipitation analysis in the microgram-scale: A new method

Summary A new method for gravimetric determinations in the microgram-scale is described. This method is based on the fact that the precipitate is not weighed together with the filter but is transferred to a separate weighingvessel using a suitable solvent. The necessary simple devices and their use are described. The following determinations were carried out with satisfying accuracy: 2,5–25g Al, 5–50g Cu and 5–50g Zn with Oxine, 2,5–25g Fe and 2,5–25g Ti withN-benzoylphenylhydroxylamine, 5–50g Ni and 5–50g Cu with salicylaldoxime, 2,52–50g Co and 2,5–50g Fe with -nitroso--naphthol and 5–50g chloride as silver chloride.

     

Determination of cadmium in tobacco smoke and zinc in tap water by solvent extraction flame atomic absorption spectrometry

Procedures are described for the determination of cadmium in tobacco smoke and zinc in tap water by flame atomic absorption spectrometry after chelation with benzyl 2-pyridyl ketone 2-pyridylhydrazone and extraction with isobutyl methyl ketone. Calibration graphs in the organic layer were linear up to 1.3 g/ml, with sensitivities of 80 ng/ml (Zn) and 71ng/ml (Cd), and limits of detection of 49 ng/ml for zinc and 38 ng/ml for cadmium. RSD values were 2.9% at 0.42 g/ml (Cd) and 4.7% at 0.17 g/ml (Zn).