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 Promedol (Trimeperidine) and Ketamine in Blood Using Gas Chromatography–Mass Spectrometry

A procedure was developed for the gas-chromatographic determination of promedol (trimeperidine) and ketamine in whole blood with mass-selective detection. The detection limit for trimeperidine and ketamine in blood is 0.05 g/mL. The analytical range is 0.1–5.0 g/mL. The maximum within-series errors in the determination of the studied compounds are no higher than 14.1% for concentrations of 0.10 g/mL and 7.47% for concentrations of 1.0 g/mL. The maximum between-series relative errors are 5.75% for concentrations of 0.10 g/mL and 2.7% for concentrations of 1.0 g/mL. The procedure can be used in toxicological and clinical analyses.     

The composition of volatile and particulate hydrocarbons in urban air

Summary The hydrocarbon composition of the particle and gas phases in the urban atmosphere has been studied by filtration and parallel adsorption on active charcoal and polyurethane foam (PUF). Gas chromatography (GC) and GC coupled to mass spectrometry (GC-MS) have been used for the analysis of the organic matter extracts obtained with each system. In the case of the particle and PUF samples these extracts were fractionated into aliphatic and aromatic compounds. This approach has allowed to identify up to 247 hydrocarbon molecules showing that C0–C5 alkylbenzenes are the major compounds in the charcoal extracts whereas C14–C23 n-alkanes, C0–C4 alkylnaphthalenes, C0–C4 alkylbiphenyls and C3–C5 alkylbenzenes are those predominantly found in the PUF materials. The particles essentially contain C17–C38 n-alkanes and parent polycyclic aromatic hydrocarbons (PAH). These qualitative differences are paralleled by a progressive concentration decrease from the more to the less volatile hydrocarbons. Thus, the total charcoal extracts average 80 g/m³, the PUF compounds represent 4 /m³ and the particle hydrocarbons 0.7 g/m³. These latter airborne materials are essentially composed of petrogenic residues 0.6 g/m³ (aliphatic fraction) whereas the pyrolytic PAH only involve 0.08 g/m³.     

Synthesis,characterization and crystal structures of heterometallic trinuclear carbonyl sulfido clusters (η5-Cp)MoFeCo- (CO)8(μ3-S) and [(η5-Cp)Mo]2Fe(CO)7(μ3-S)

HFe2Co(CO)9(3-S) reacts with (5-Cp)Mo(CO)3Cl in refluxing THF to give heterometallic trinuclear clusters (5-Cp)MoFeCo(CO)8(3-S) and [(5-Cp)Mo]2Fe(CO)7-(3-S), which have been characterized by elemental analyses, i.r., 1H- and 13C-n.m.r. and X-ray crystal structure determination. An electrophilic addition–elimination sequence is proposed for their formation.     

Characterization of [Ni(py)4]Cl2 and its thermal decomposition

The stepwise thermal decomposition of [Ni(py)₄]Cl₂ was studied by means of a derivatograph. The stepwise mode of thermal decomposition allowed the preparation of new complexes. X-ray powder diffraction and IR methods were used to study the structures of the decomposition intermediates. [Ni(py)₄]Cl₂ was applied as a model substance. The decompositions of a great number of complex compounds of similar type have been reported, but only a few of them have been investigated structurally by single-crystal X-ray diffraction techniques due to the difficulty of obtaining large single-crystals.

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Zusammenfassung Die schrittweise thermische Zersetzung von [Ni(py)₄]Cl₂ wurde mit einem Derivatographen untersucht. Diese Methode ermöglicht die Darstellung neuer Komplexverbindungen. Zur Untersuchung der Struktur der intermediären Zersetzungsprodukte wurden ebenfalls XPD und IR-Spektroskopie angewandt. [Ni(py)₄]Cl₂ wurde als Modellsubstanz gewählt. Eine große Zahl ähnlicher Komplexverbindungen ist bekannt, aber nur von wenigen wurde die Kristallstruktur wegen der Schwierigkeiten, entsprechend große Einkristalle zu erhalten, durch Einkristall-Röntgendiffraktometrie bestimmt.

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[Ni(py)₄]Cl₄) . . , .

     

Nonisothermal kinetics of independent reactions

A general approach to the solution of peak seperation problem applicable not only in nonisothermal kinetics, but also in chromatographic, spectroscopic and polarographic studies of catalysts is suggested.

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, , , , , .

     

Localization of gallium in erionite type Ga?Al zeolites by71Ga,27Al and29Si NMR

The state of Al³⁺, Ga³⁺ and Si⁴⁺ in erionites obtained by hydrothermal crystallization from Ga–Al–Si gels has been examined. The results suggest that gallium cations can isomorphously substitute a part of silicon cations in the zeolite framework, to a notable extent in the sites having no aluminium cations in the second coordination sphere of silicon.

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Al³⁺, Ga³⁺ Si⁴⁺ , . , , .

     

Calorimetric study of molecular interactions in mixtures of substances containing carbonyl and dialkylamino groups

A Tian-Calvet type calorimeter has been used to determine molar excess enthalpies at 298.15 K as a function of concentration for mixtures ofN,N-dialkylated aminoketones or amides+n-heptane. These data are examined on the basis of a quasi-chemical theory using group-surface interactions. The occurrence of the hetero-proximity effect between -CO- and-N < groups is suggested by the variation of the interchange parameters.

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Zusammenfassung Ein Kalorimeter vom Tian-Calvet-Typ wurde zur Bestimmung der molaren Überschußenthalpie von Mischungen vonn-Heptan mitN,N-dialkylierten Aminoketonen bzw. Amiden bei 298.15 K in Abhängigkeit von der Konzentration verwendet. Die erhaltenen Daten wurden nach der quasi-chemischen Theorie unter Verwendung von Wechselwirkungen zwischen Gruppen und Überfläche ausgewertet. Das Auftreten des hetero-proximity-Effektes zwischen-CO- und -N <-Gruppen wird durch Veränderung der Austauschparameter angezeigt.

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- 298.15 N,N- -. - , . -- -N < .

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This is evidence indeed that proton acceptors, such as tertiary amines, shift the ketoenol equilibrium towards the formation of enols [3].     

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     

Application of l-cysteine-capped nano-ZnS as a fluorescence probe for the determination of proteins

Nanometer-sized l-cysteine-capped ZnS particles have been synthesized and used as a fluorescence probe to investigate the effect of proteins on fluorescent intensity. With =190 nm, maximum and constant synchronous fluorescence enhancement was produced at 267 nm and pH 5.12 in the presence of proteins. A highly sensitive synchronous fluorescence method for the rapid determination of proteins has been developed. Under optimum conditions, calibration graphs are linear over the range 0.03–8.0 g mL^–1 for bovine serum albumin (BSA), 0.01–6.0 g mL^–1 for human serum albumin (HSA), 0.05–8.0 g mL^–1 for -globulin (-G), and 0.04–4.0 g mL^–1 for ovalbumin, respectively. The relative standard deviations of seven replicate measurements were 1.75% for 1.0 g mL^–1 BSA, 1.90% for 1.0 g mL^–1 HSA, 1.65% for 1.0 g mL^–1 -G, and 2.32% for 1.0 g mL^–1 ovalbumin.