Spektrophotometrische Bestimmung von Nickel und Kobalt nebeneinander mit N,N'-Bis-(o-aminobenzyliden)-?thylendiamin

Zusammenfassung N,N'-Bis-(o-ammobenzyliden)-äthylendiamin (ABAD) bildet mit Ni²⁺ und Co³⁺ stabile Chelate, wobei schon durch Luftsauerstoff eine Oxydation von Co^IIzu Co^III-ABAD erfolgt. Ni-ABAD kann quantitativ mit Benzol extrahiert und spektrophotometrisch bei 486 nm bestimmt werden. Co^III-ABAD wird in der wäßrigen Schicht bei 430 nm bestimmt. Die Grenzkonzentrationen betragen 0,5 g Ni/ml und 0,6 g Co/ml in Konzentrationsverhältnissen von 1001 bis 1100. Die Methode ist ebenfalls zur quantitativen Bestimmung von Co neben Cu geeignet.

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Summary N,N'-Bis-(o-aminobenzylidene)-ethylenediamine (ABAD) quantitatively reacts with Ni²⁺ and Co³⁺ to form stable chelates. Co^II-ABAD is easily oxidised by air to Co^III-ABAD. Ni-ABAD can be extracted with benzene and determined spectrophotometrically at 486 nm, Co^III-ABAD is determined in the water-layer at 430 nm. The limit of detection is 0.5 g Ni/ml and 0.6 g Co/ml by the ratio from 1001 to 1100. The method is also suitable for separation and determination of Co in the presence of Cu.

     

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.     

Trace determination of beryllium by heavy ion activation analysis

A novel procedure for measuring the concentration of trace beryllium in different samples has been studied using¹¹B heavy ion activation analysis. The specific reaction,⁹Be/¹¹B, 2n/¹⁸F, is sensitive and selective when using a 10 MeV¹¹Be³⁺ bombardment energy. The detection limit for a nondestructive analysis is 0.1 ng for a 2 h irradiation in a A cm^–2 beam current. A precision of 12% was achieved at the 50 g g^–1 level. Beryllium has been determined in a standard beryllium-copper alloy NBS-SRM C1123. Glass samples containing up to 61 trace elements were also analyzed nondestructively. When using a clean vacuum irradiation chamber, the technique might allow ultra-trace determinations, dealing with solid samples of a few milligrams.     

Analysis of anthropogenic and biogenic lipids in the aerosol of a coastal area in East Mediterranean Sea

Summary The concentrations of lipids were determined in atmospheric particle samples, collected seasonally, in an urban coastal area of the Island of Crete. Lipid compound classes, such as n-alkanes, hopanes and steranes, PAH, fatty alcohols, fatty acids and fatty acids selts, were determined by GC-FID and GC-MS analysis. The concentrations ranged between 56–215 ng/m³ for n-alkanes, 10–52 ng/m³ for PAH, 2–31 ng/m³ for fatty alcohols, 13–279 ng/m³ for fatty acids and 24–220 ng/m³ for fatty acid salts. -Oxocarboxylic acids were also determined as salts, indicating the atmospheric oxidation of unsaturated fatty acids.     

NMR Study of the Stoichiometry, Stability, and Ligand Interchange of Silver Ion-Hexathia-18-crown-6 Complex in Binary Dimethyl Sulfoxide Solvent Mixtures at 300 K

Proton NMR was used to study the complexation reaction between silver ion and hexathia-18-crown-6 in a number of binary mixed solvents of dimethyl sulfoxide with acetonitrile and methanol. Formation constants for the resulting 1:1 complexes in different solvent mixtures were determined by computer fitting of the chemical shift-mole ratio data. The influence of solvent composition on the stability of the resulting complex is discussed. The exchange kinetics of Ag⁺-hexathia-18-crown-6 in 70-30 wt.% dimethyl sulfoxide-acetonitrile and 75-25 wt.% dimethyl sulfoxide-methanol were studied by proton NMR line-shape analysis. In both solvent mixtures, the exchange of thiacrown ether between the free and complexed sites was found to proceed via a dissociative pathway. The exchange rates and the activation parameters E _a, H , S, and G for the ligand exchange were determined and the influence of solvent properties on these parameters discussed.     

Steroids

Conclusions 1. It has been established that the hydrogenation of 11-hydroxy-16-methylpregn-4-ene-3,20-dione and of 16-methylpregn-4-ene-3, 11 20-trione over 10% palladium on calcium carbonate in pyridine takes place stereospecifically and is determined by the substituent at C₁₁.2. It has been shown that a 16-methyl group has practically no influence on the stereochemical directivity of the hydrogenation of the ethylenic bond of the ⁴-3-oxo system.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 1, pp. 53–56, 1970For part XXXVI se KhPS [Chemistry of Natural Compounds], 6, 33, 1970 [in this issue].     

Theory of chirality functions,generalized for molecules with chiral ligands

The theory of chirality functions described in a previous publication is generalized to allow for chiral ligands. In the earlier theory, all symmetry operations of the molecular frame could be thought of as permutations of the ligands among the sites; in the present work, improper rotations not only permute the ligands, but convert them into mirror images. The group that generates all isomers from a given ordered molecule belonging to a frame with n sites is now the hyperoctahedral group of order 2ⁿ n! consisting of all possible combinations of permutations and site reflections. The representation theory of these groups is described, and applied to the problem of constructing qualitatively complete chirality functions, and of deciding which ligand partitions, and which isomer mixtures, are chiral. It is found useful to classify chiral representations of the covering group as ligand specific and class specific. The ligand specific representations describe chiral properties which are common to all frames and arise purely from the chirality of the ligands, while the class specific representations describe the chiral properties of the frame. A number of examples are explicitly worked out.     

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.     

Synthesis of heterocycles on the basis of 1,5-diketone hydrazones. 2. Oxidative cyclization of δ-bicyclanone bis(phenylhydrazones) as a method for the synthesis of substituted 2-phenyl-4R-Δ1(sa)-octahydrocinnoline-3-spirocy clohexanes

The oxidation of -bicyclanone bis (phenylhydrazones) with oxygen or ferric chloride leads to the formation of 2-phenyl-4R-^1(sa)-octahydrocinnoline-3-spiro-1-cyclohexan-2-one phenylhydrazones. The structures of these compounds were proved by the ¹³C NMR, IR, and mass spectra, as well as by transformations in acidic media to the corresponding keto derivatives and tetrahydrocarbazole derivatives.See [1] for Communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 821–825, June, 1983.     

Plutonium in soils, bottom sediments and lichen near peaceful nuclear explosion sites in the Republic of Sakha (Yakutia)

During the 1974–1987 period 12 paceful nuclear explosions were conducted in the Republic of Sakha (Yakutia). For the first time^239,240Pu and²³⁸Pu concentrations were determined in samples of soils, bottom sediments and lichen taken at the Craton-3 and Crystal nuclear explosion sites. At the Craton-3^239,240Pu concentrations in the range 6.2 mBq/g to 5.9 Bq/g samples of soil and^239,240Pu concentrations up to 7.4 Bq/g in samples of lichen were observed.^239,240Pu concentration measurements in bottom sediments of a stream washing out the banking around the borehole of Craton-3 show that plutonium migrates in the direction of the Markha river. At the Crystal site local plutonium concentrations up to 35 Bq/g in soil and 1.8 Bq/g in lichen were observed.     

Factors influencing the stability of H-bonds between guanidinium ions and counter ions or neutral ligands

Guanidinium ions can form H-bonds either with counter ions with proton acceptor sites or with neutral ligands. In solvents as nitrobenzene their formation constants K _h depend a priori on the pK _a of the guanidinium ion in water. Nevertheless the sequence of these constants is perturbed by two other factors: the number of equivalent N–H sites and the steric hindrance of the substituents of the guanidinium ion. In this work the stability constants K _h of guanidinium and methyl or phenyl substituted guanidinium ions with counter ions and neutral ligands were determined from the conductimetric data in nitrobenzene at 25°C. The constants are first divided by the number of available proton donor sites yielding K _h ^/* . Considering only the cases where steric hindrance is not important, correlations are established between log K _h ^/* and the pK _a of the guanidinium ion in water, also corrected for the number of available sites. The effect of steric hindrance in the other systems can be estimated from the comparison of the actual value of K _h ^/* with that of K _h ^/** predicted by the correlations. To a rough approximation, the effect of the steric hindrance can be described by factors _i characterizing the guanidinium ion and _j characterizing the partner as expressed by the relation log₁₀K _h ^** /K _h ^* = _ij.     

Secondary ion emission of selected transition metals under nitrogen oxides

The emission of various positive secondary ions has been investigated for polycrystalline targets of Ti, V, Cr, Nb, Ta, Co, Ni, Cu, Pd and Pt, which were bombarded by Ar⁺ ions under dynamic SIMS (DSIMS) conditions in the presence of the gaseous nitrogen oxides N₂O, NO and NO₂ at fixed pressure and under residual gas. Besides ions of the Me⁺ type several fragmentary ions (e.g. N⁺, O⁺, NO⁺, MeN⁺ and MeO⁺) and also cluster ions Me _x O _y ⁺ (x 2, 0 y 2) were detected. Signals of a more molecular type with respect to the reactant gas, e.g. MeNO⁺, were only found for Co, Ni, Cu, Pd and Pt. From this, one may infer that for the other targets the nitrogen oxides will exist preferentially in a dissociatively adsorbed state at the metal surface. Several aspects of secondary ion emission can be explained assuming a different degree of oxidation for the metals under the influence of reactant gas.Part of the dissertation     

The determination of lead in environmental and geological materials by proton activation analysis

Lead is determined in environmental samples and in rocks using the^206,207,208Pb(p,xn)²⁰⁶Bi reaction. Bismuth is separated by anion exchange or by extraction with antimony diethyldithiocarbamate. Sources of errors such as volatilization of the matrix due to heating during the irradiation, variations of the abundance of the lead isotopes and the standardization were studied in detail. For concentrations between 11 mg/g and 3.7 g/g the relative standard deviation ranges from 2.6 to 5.4%. The detection limit is 10 ng/g.     

Analysis of nitrated polycyclic aromatic hydrocarbons by liquid chromatography with fluorescence and mass spectrometry detection: air particulate matter, soot, and reaction product studies

Polycyclic aromatic hydrocarbons (PAH) and their nitrated derivatives (nitro-PAH) are environmental pollutants which pose a threat to human health even at low concentration levels. In this study, efficient analytical methods for the analysis of nitro-PAH and PAH (extraction, clean-up, chromatographic separation, and spectrometric detection) have been developed, characterized, and applied to aerosol samples. The separation and quantification of 12 nitro-PAH was carried out by reversed-phase high performance liquid chromatography (HPLC), on-line reduction, and fluorescence detection. The detection limits were in the range of 0.03–0.5 g L^–1 (6–100 pg in the investigated sample aliquots), and the recovery rates from soot samples were 70–90%. Nitro-PAH and PAH concentrations have been determined for different types of soot and for urban, rural, and alpine fine air particulate matter (PM2.5). For the first time, trace amounts of nitro-PAH have been detected in a high-alpine clean air environment. The on-line reduction and fluorescence technique has been complemented by atmospheric pressure chemical ionization time-of-flight mass spectrometry (APCI-TOF-MS). The MS detection allowed the analysis of partially nitrated and oxygenated PAH in laboratory studies of the heterogeneous reaction of PAH on soot and glass fiber substrates with gaseous nitrogen oxides and ozone. It led to the tentative identification of a previously unknown nitrated derivative of the particularly toxic PAH benzo[a]pyrene (BaP-nitroquinone), and provides the first experimental evidence that PAH-nitroquinones can be formed by reaction of PAH with atmospheric photooxidants.     

Structures of three substituted pentacyclo[5.4.0.02, 6.03, 10.05, 9]undecanes and a computational analysis of bond lengths

5-Methyl-2-phenylpentacyclo[5.4.0.0^{2, 6}.0^{3, 10}.0^{5, 9}]undecane-8, 11-dione,5-methyl-2-phenylpentacyclo [5.4.0.0^2,6.0^3,10.0^5,9]undecane-8-one-11-ol,and 5-methyl-2-phenylpentacyclo[5.4.0.0^2,6.0^3,10.0^5,9]undecane-8,11-diol are three cage compounds which differ only in the oxidation state at C(8) and C(11). The three compounds contain a four-membered, a six-membered, and four five-membered rings fused into a cagelike structure. An X-ray structure analysis shows the C(1)-C(7) and C(9)-C(10) bonds in the diketo cage to be 1.606(2) and 1.586(2) Å, which are significantly longer than in the other two molecules. In order to assess the effects of strain, steric, and electronic factors in these compounds, we investigated the unsubstituted parent cage compounds and a series of derivatives by molecular mechanics (MM3), AMPAC (AM1), MOPAC (PM3), and GAUSSIAN 90 calculations. These data suggest that dipolar through space interactions are responsible for the bond elongation and not a _– ^* interaction, which has been postulated in parallel-systems originating from a common bond. A small degree of _– ^* through-bond interaction may contribute to the lengthening in the dimethylene cage analogues.     

Triazole derivatives as analytical reagents. Part V. Analytical studies of β-resorcylazomercaptotriazole (METRIAREZ-β) and γ-resorcylazomercaptotriazole (METRIAREZ-γ) acids

METRIAREZ- and -, two new derivatives of 5-mercapto-1,2,4-triazole with - and -resorcylic acids have been synthesized and their physicochemical and chelating properties determined. With metal ions havingp andd electrons they form water-soluble coloured chelates at L M molar ratios of 1 1 with Cu²⁺ and Pb²⁺ ( and ), Hg²⁺ and Zn²⁺ () and Cd²⁺, In³⁺ and Bi³⁺ () and 2 1 with Fe³⁺, Fe²⁺, Co²⁺ and Ni²⁺ ( and ) and Zn²⁺ (). The chelates are non-extractable by organic solvents. The stability constants of these complexes, as well as their spectrophotometric sensitivity and extinction coefficients were determined. Iron and zinc in multivitamin tablets were determined spectrophotometrically using the ligands.     

Stability Constants of Cu(II) Hydroxypropylenediaminetetraacetates

Equilibrium of complexation between 2-hydroxypropylene-1,3-diamine-N,N,N,N-tetraethanoic acid (H₄L) and u²⁺ ions was studied by potentiometric and spectrophotometric methods. Stability constants of CuL^2– and CuHL^– complexes were determined at 298.15 K and I = 0.5 (KNO₃).     

A conductance study of the association of alkali cations with 1,13-dibenzo-24-crown-8 in acetonitrile

A conductance study concerning the association of Na⁺, K⁺, Rb⁺, and Cs⁺ with 1,13-dibenzo-24-crown-8 in acetonitrile has been carried out at 35, 30, 25, 20, and 15°C. The observed molar conductivities were found to decrease significantly for mole ratios less than unity. A model involving 11 stoichiometry has been used to analyze the conductivity data. The stability constant, K, and the molar conductivity _C for each 11 complex were determined from the conductivity data by using a nonlinear least squares curve fitting procedure. The binding sequence, based on the value of log K at 25°C, is found to be Rb⁺>Cs⁺>K⁺>Na⁺. Values of H^o and S^o are reported and their significance is discussed.     

Rapid determination of four polycyclic aromatic hydrocarbons by HPTLC using nano plates

Summary Reversed phase nano plates (HPTLC) have been used for a rapid analysis of a number of PAH (benzo(ghi) perylene, benzo(a)pyrene, benzofluoranthenes and benz(a) anthracene) regularly present in the ambient air. A definite volume of extract is applied to a silica gel column and eluated with cyclohexane. The concentrated eluat is spotted on plates in streak form. A twofold development with acetonitrile/dichloromethane/water (911) results in a complete distinct separation of the four components in 7 min. Evaluation of sample spots is accomplished by measuring the fluorescence intensity registered as a peak at 366 nm. The evaluated peak against benzo(b)fluoranthene is characterized as benzfluoranthenes since the benzfluoranthene isomers are not separated by this procedure. This method has a good reproducibility (rel. standard error 4.4%) and can be easily adopted to the quantitative determination of the four PAH in ambient air and in indoor air involving short sampling periods. The minimum detectable limits on these plates for benz(a) anthracene is 2 ng and 0.2 ng for the three other PAH.

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Schnelle Bestimmung von vier polycyclischen aromatischen Kohlenwasserstoffen durch HPTLC mit Nano-Platten

Zusammenfassung Für eine schnelle Bestimmung von einigen PAH, die stÄndig in der Au\enluft auftreten, werden Nano-Platten (HPTLC) mit reversed phase verwendet. Ein bestimmtes Extraktvolumen wird auf eine KieselgelsÄule gegeben und mit Cyclohexan eluiert. Das konzentrierte Eluat wird strichförmig auf der Platte aufgetragen. Eine zweifache horizontale Entwicklung mit Acetonitril/Dichlormethan/ Wasser (911) bedingt eine deutliche Auftrennung der vier Komponenten nach 7 min. Die Auswertung erfolgt durch Messung der FluorescenzintensitÄt bei 366 nm. Da bei diesem Verfahren die Isomere des Benzo(b)fluoranthens nicht getrennt werden, mu\ die dem Standard Benzo(b)fluoranthen zugeordnete PeakflÄche als Benzfluoranthene bezeichnet werden. Die Methode zeigt eine gute Reproduzierbarkeit (rel. Standardabweichung 4,4%) und kann zur Bestimmung dieser vier PAH in der Au\enluft als auch in der Raumluft bei kurzen Probenahmezeiten Anwendung finden. Die Nachweisgrenzen auf der Nano-Platte betragen für Benz(a) anthracen 2 ng, für die drei übrigen PAH 0,2 ng/Fleck.