Hydrazobenzene cannot be oxidized to azobenzene with hydrogen peroxide in ethanol-containing medium. Vanadium(V) ions catalyze the oxidation; in their presence the reaction takes place rapidly. A thermometric (DIE) method was developed for the determination of hydrazobenzene, based on the oxidation reaction with hydrogen peroxide catalyzed by vanadium(V). The reaction is initiated by the addition of the solution of the catalyst, which is applied in small amount (100Μl). Thus, the application of the immersion pipette is not necessary. The standard deviation of the determination is ±0.42 mg hydrazobenzene in 50 ml ethanol.

The equilibrium geometries and harmonic force fields of PH₃ and PH₅ are calculated in an ab initio way including electron correlation. The results for PH₃ are in very good agreement with experimental values, whereas those for PH₅ have to be regarded as predictions. We find for PH₅ in its equilibrium D_3h structure r_ax = 1.47 Å, r_eq = 1.42 Å and the harmonic vibration frequencies in Table 7 given under the heading “CEPA”. The barrier for Berry inversion is 2 kcal/mol. The ab initio calculation of phosphoranes such as PH₅ not only requires the inclusion of polarization functions (d on P and p on H) but is also very sensitive to the choice of these polarization functions. This problem is taken care of by a detailed comparison of various basis sets. It is confirmed that a (10/6) basis for P in “double zeta contraction” is better balanced than a (12/9) basis in “double zeta contraction” and that the total energy is not a good criterion for the quality of a basis.

Zusammenfassung

Der Ionenassoziationskomplex von Bis(neocuproin)-Cu(I) mit Nitrat wurde als neues elektroaktives Material für eine nitrationenselektive Elektrode verwendet. Zwei verschiedene Typen wurden hergestellt: eine Flüssigkeitselektrode und eine PVC-Membranelektrode mit direktem Festkontakt. Empfindlichkeit und Selektivität wurden untersucht und die Vor- und Nachteile beider Typen werden beschrieben. Die PVC-Membranelektrode wurde zur Nitratbestimmung in Wasser (>0,2 ppm NO ₃⁻ -N) benutzt.

The present paper describes the use of SIMS for obtaining analytical data on a number of diverse systems. Of particular importance is a comparison of SIMS with other surface analytical techniques each applied to the same sample set. The emphasis of our work is the importance of multi-technique surface analysis; the present paper focuses on how SIMS complements techniques such as ESCA, AES, ISS and EXAFS. Studies are reported on systems as diverse as boron oxides, organic polymers, trace metal analysis, supported metal catalysts, alloys and biomaterials.

Adduct formation between U(TTA)₄ and neutral donors triphenyl phosphine oxide (TPPO), tri-n-butyl phosphate (TBP) and methyl-isobutyl ketone (MIBK) in benzene was studied by absorption spectra. All the three donors form 1∶1 adduct with U(TTA)₄. The adduct formation constants calculated from the spectral changes were 5·2×10⁴, 1·1×10³ and ∼0·8 for the adducts with TPPO, TBP and MIBK respectively. The adduct formation apparently increases the coordination number of U(IV) from 8, in the U(TTA)₄ to 9 in the adduct formed.

The examination of samples of various commer-cially available vegetable oils (olive oil, sunflower oil, thistle oil, linseed oil, plant germ oil, etc.) and of various samples of margarine for the presence of vola-tile N-nitroso-compounds yielded the following results. By means of the above mentioned procedure (gas liquid chromatography — AFID gas liquid chromatography — TEA), N-nitrosodimethylamine (NDMA) was found to be present in 21 of 61 dif-ferent samples of vegetable oil, in concentrations ranging from < 1 μg/kg to 23 μg/kg. 18 samples con-tained N-nitrosodiethylamine (NDEA) in concentra-tions varying between < 1μg/kg and 27.8 μg/kg. 37 out of 107 different samples of margarine were shown to contain N-nitroso compounds. N-nitroso-dimethylamine was found to be present in 15 samples. The range of concentrations determined was between < 1 μg/kg and 5.8 μg/kg. 33 samples con-tained N-nitrosodiethylamine in concentrations varying between < 1 μg/kg and 7.5 μg/kg.