Neutron activation analysis of asbestos from Canada

Concentrations of Al, Au, Br, Ce, Cl, Co, Cr, Fe, K, La, Mg, Mn, Na, Ni, Sb, Sc, Sm, Srm and V were determined in 6 samples of asbestos from Canada. They were equal to (in ppm): Al 1660–3430; Au 0.03–0.04; Br 3.1–11.7; Ce 1.7–4.8; Cl 116–331; Co 35–83; Cr 200–2060; Fe 29300–42200; K 125–867; La 0.28–1.03; Mg 24–25.9%; Mn 418–545; Na 364–1610; Sb 0.65–1.46; Sc 3.73–5.57; Sm 0.09–0.3; Sr 26.7–41.4; V 8.4–14.3. Five toxic elements were found in asbestos; Cr, Mn, Ni, Sb and V.     

Microdistributions of Electrolytic Alloys and Their Components

Microdistributions of Cu–Ni and Cu–Co alloys electrodeposited from pyrophosphate; Ni–Cu, from sulfate–chloride and pyrophosphate–ammonium; Cu–Zn, from pyrophosphate and cyanide; Cu–Cd, from sulfate and pyrophosphate; and Ni–Cd, Ni–Co–Cd, and Zn–Cd, from sulfate, sulfate–chloride, pyrophosphate, chloride–ammonium, and acetate electrolytes are studied. The coatings' microprofile depends on the kinetics of reduction of each component and mutual influence of electrochemical processes at the cathode. Copper accelerates and cadmium inhibits the reduction of the second component of alloys, no matter the electrolyte type, reduction kinetics, and metal nature. In antileveling conditions, the diffusion-controlled Cu reduction accelerates the reduction of the second component of alloys and ensures deposition of coatings whose microprofiles are more uniform than expected from diffusion limitations only. Depolarizing action of Cu during the Cu–Zn deposition from a cyanide electrolyte can completely neutralize differences in the rates of supply of reduced metal ions; hence a constant chemical composition of the coating over its microprofile. Inhibiting action of the diffusion-controlled Cd deposition provides for leveling properties of electrolytes from which Ni–Cd, Ni–Co–Cd, and Zn–Cd alloys are deposited; the chemical composition of these deposits is nonuniform over their microprofiles.     

Towards the understanding of the spectroscopic behaviour of the C–H oscillator in C–HO hydrogen bonds: the effect of solvent polarity

The effect of solvent polarity versus specific C–HO contacts on the vibrational νC–H mode is studied using CHCl₃ as a model system. Ab initio SCI–PCM calculations show that the overall shift of the νC–H band, sometimes ascribed to the C–HO hydrogen bonding, can in fact be explained by the electrostatic interaction with a dielectric environment. The presence of a new νC–H band – assigned to the C–HO bonded forms – remains as the most reliable evidence of C–HO hydrogen bonding.     

Nanoaggregates of ABC-type triple hydrophilic block copolymers by binding of cationic surfactant

A triple hydrophilic block copolymer comprised of poly(ethylene oxide), poly(sodium 2-acrylamido-2-methylpropanesulfonate), and poly(methacrylic acid) (PEO–PAMPS–PMAA) does not form a micelle by itself when it is dissolved in water. However, in the previous paper, we fabricated the nanoaggregates of PEO–PAMPS–PMAA and cationic surfactant, such as cetyltrimethylammonium chloride (CTAC), by insolubilizing the anionic PAMPS and/or PMAA blocks of the polymer with CTAC only at high pH. In this paper, we fabricated the nanoaggregates of dodecyltrimethylammonium chloride (DTAC) and PEO–PAMPS–PMAA in a wide range of pH to examine the effect of ionization of the PMAA blocks of the polymer on the aggregates formation of PEO–PAMPS–PMAA. The properties of the nanoaggregates are affected by the ionization of PMAA block of the polymer. DTAC (C12 alkyl chain) was employed instead of CTAC (C16 alkyl chain) to reveal the effect of alkyl chain length of surfactant on the aggregate formation of PEO–PAMPS–PMAA. The properties of PEO–PAMPS–PMAA nanoaggregates also depend on the structure of surfactant. The binding of DTAC to PEO–PAMPS–PMAA was monitored by electrophoresis measurements, while the formation of DTAC/PEO–PAMPS–PMAA nanoaggregates was confirmed by scanning electron microscopy, dynamic light scattering measurements and fluorescence spectroscopy.     

Effect of preparation pH on pore structure of silica gels

Surface characterization of silica gels prepared at different gelation pH from water glass and sulphuric acid were made by argon adsorption at 77 K using continuous volumetric method. While microporous silica gels prepared in the pH range of 1–3 had BET surface areas of 504–571 m² g^–1, total pore volumes of 0.26–0.31 cm³ g^–1 and micropore volumes of 0.16–0.23 cm³ g^–1, mesoporous silica gels prepared in the pH range of 3.36–0.65 had BET surface areas of 374–530 m² g^–1 and pore volumes of 0.61–0.79 cm³ g^–1.     

Effect of temperature on the selectivity of the extraction of lanthanides with dibutylphosphoric acid from thiocyanate solution

Extraction coefficients and separation factors of all lanthanides were determined in the system: dibutylphosphoric acid /HDBP/ - 3M NH₄NCS, in the temperature range of 15–50 °C. The values for the separation factors for such pairs as: Gd–Tb and Er–Tm, are higher than 4, those for the pair of Tb–Dy are higher than 3, and those for the La–Ce, Pm–Sm, Dy–Ho, Ho–Er and Tm–Yb pairs are higher than 2. The influence of temperature on the separation factors of light /La–Gd/ and heavy /Gd–Lu/ lanthanides is discussed and compared with that observed for the extraction from the nitric acid solutions. The results are also discussed in the light of the double-double effect and outer-, vs. inner-sphere complexation in the lanthanide series.     

Polarographic and voltammetric determination of trace amounts of 2-nitronaphthalene

The polarographic behaviour of 2-nitronaphthalene was investigated by DC tast polarography (DCTP) and differential pulse polarography (DPP), both at a dropping mercury electrode, and differential pulse voltammetry and adsorptive stripping voltammetry, both at a hanging mercury drop electrode. Optimum conditions have been found for the determination of 2-nitronaphthalene by the given methods in the concentration ranges of 2×10^–6–1×10^–4, 2×10^–7–1×10^–4, 1×10^–8–1×10^–4 and 2×10^–9–1×10^–8 M, respectively. Practical applicability of these techniques was demonstrated by the determination of 2-nitronaphthalene in drinking and river water after its preliminary separation and preconcentration using liquid–liquid and solid-phase extraction with limits of determination of 3×10^–10 M (drinking water) and 3×10^–9 M (river water).     

Analysis of High-Purity Volatile Compounds

The current status of the analysis of high-purity volatile substances is considered. Two types of impurities in high-purity volatile substances were distinguished: molecularly dissolved substances and suspended particles. The main factors that restrict the limiting capabilities of analytical techniques were revealed. The attained detection limits were 10^–8–10^–10% for metal impurities, 10^–4–10^–8% for organic substances, 10^–5–10^–9% for water, and 10^–5–10^–7 for permanent gases. Suspended particles of 0.04–0.003 m in size were determined by light scattering.     

Voltammetric Determination of Sulfide Ions

Procedures were proposed for the voltammetric determination of S^2– at a mercury-film electrode. They are based on the oxidation of S^2– at –0.79 to –0.80 V and on the reduction of HgS, the product of the oxidation of S^2–, at –0.76 to –0.96 V in a 1 M NaOH solution. The anodic and cathodic currents are linear functions of S^2– concentration in the ranges from 1 × 10^–5 to 1 × 10^–4 M and from 2 × 10^–6 to 1 × 10^–4 M, respectively.     

Synthesis,electrochemical and magnetic properties of new macrocyclic copper(II) complexes derived from 2,6-diacetyl-4-4-methylphenol

A series of binuclear macrocyclic copper(II) complexes [Cu2Lm,n](ClO4)2·xH2O have been prepared in which the two copper(II) ions are placed in two geometrically distinct co-ordination environments. The macrocycles with two 2,6-bis(iminomethyl)-4-methylphenol entities combined through two different lateral chains, –(–CH2–)–m and –(–CH2–)–n (m = 2 or 3, n = 2 to 5) were synthesized by stepwise cyclization. Cyclic voltammetry shows the presence of two reduction couples: CuIICuII CuICuII and CuIICuI CuICuI. The comproportionation constants, Kcom, for the mixed valence CuICuII complexes have been determined electrochemically. The Kcom value increases in the order of the macrocycles: (L2,2)^2–<(L2,3)^2–<(L2,4)^2–<(L2,5)^2– and (L3,3)^2–<(L3,4)^2–<(L3,5)^2–. Cryomagnetic investigations (80–300K) reveal a moderately strong antiferromagnetic spin exchange between the copper(II) ions within each complex (J = –210 to –390 cm–1).     

Spectroscopic studies of the behaviour of the AgNO3−HNO3 — Tetrabutyl dithiopyrophosphate extraction system

A very efficient extraction of silver with tetrabutyl dithiopyrophosphate (TBDTPP) is followed by dramatic changes in the structure of the extractant molecule. The IR and NMR spectroscopic studies have revealed that in the presence of Ag⁺ and NO ₃ ^– ions the TBDTPP molecule rearranges first into a molecule containing a P–S–P bridge and one P=O group instead of P–O–P and P=S, respectively, and then into a molecule containing two P–S–C and two P=O groups at a P–O–P bridge.     

Radioisotope excited EDXRF analysis of sediment core samples from the southern part of the Black Sea +

In all 43 sediment samples were collected as gravity cores in depthfrom 70 to 150 cm, from the 20 sampling sites of the continental slope ofthe southern part of the Black Sea, during 1978. The samples were quantitativelyanalyzed by radioisotope excited energy dispersive X-ray fluorescence spectrometry(EDXRF) using fundamental parameter technique (FTP). The investigated sedimentsamples were the organic rich-mud components of the core samples, which wereknown as rich in metals. The metal concentration ranges were as follows: Ca(3.1–12.9%), Ti (1000–2000 µg/g), V (40–150 µg/g),Cr (30–200 µg/g), Mn (200–1500 µg/g), Ni (25–100µg/g), Cu (20–70 µg/g), Zn (20–50 µg/g), Br(15–670 µg/g), Rb (5–90 µg/g), Sr (80–700 µg/g),Y (10–20 µg/g), Mo (10–111 µg/g), Zr (20–190µg/g), Cd ( <1–5 µg/g), Sb ( <1–5 µg/g),I (10–430 µg/g), Ba (100–1650 µg/g), La (5–18µg/g), Ce (12–38 µg/g) and Nd (6–17 µg/g). Thesediment cores systematically collected in 1978 by Mineral Research and ExplorationInstitute of Turkey (MTA) are the oldest available sediment samples from theTurkish coastline of the Black Sea. Therefore, the results may be used asreferences for monitoring possible future metal pollution.     

Spectroscopic study of vinylidene chloride—Vinyl chloride copolymers

Summary Deuteration technique was applied to study the micro structures of copolymer series VDC/VC by infrared spectroscopy and high resolution NMR. The CH₂ bending modes of chlorine atom containing polymers assigned as follows; –CCl₂CH₂CCl₂– 1405 cm^–1 (cryst.) and 1410 cm^–1 (amorph.), –CHClCH₂CCl₂– 1422 cm^–1, –CHClCH₂CHCl– 1428 cm^–1 (cryst.) and 1432 cm^–1 (amorph.) –CHClCH₂CH₂CHCl– 1445 cm^–1 and –CCl₂CH₂CH₂CCl₂– 1448 cm^–1. This infrared interpretation shows that only the head to tail addition occurs in the copolymerisation. Nine peaks of the methylene protons were observed clearly in the NMR spectra of the copolymers. The study of the deuterated copolymers revealed that the effects of the chemical groups until the third at both sides from the marked methylene and the stereo configuration of long VC part should be considered to assign the NMR spectra. The CCl₂ group made the chemical shift of the methylene proton to appear at lower magnetic field and the CHCl group gave the opposite behavior.

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Zusammenfassung Mit deuterierten Monomeren wurde die Mikrostruktur der Copolymerenserie Vinyliden-Chlorid/Vinyl-Chlorid im Infraroten und mit hochauflösender Kernresonanz untersucht. Für die Biegeschwingung der Chloratome enthaltenden Polymeren der Methylengruppe ergeben sich folgende Werte: –CCl₂CH₂CCl₂– 1405 cm^–1 (krist.) und 1410 cm^–1 (amorph.), –CHClCH₂CCl₂– 1422 cm^–1, –CHClCH₂CHCl– 1428 cm^–1 (krist.) und 1432 cm^–1 (amorph.), –CHClCH₂CH₂CHCl– 1445 cm^–1 und –CCl₂CH₂CH₂CCl₂– 1448 cm^–1.Diese Interpretation des Infraroten zeigt, daß nur die Kopf-Schwanz-Addition bei der Copolymerisation stattfindet. Neun Maxima des Methylenprotons wurden deutlich in den NMR-Spektren der Copolymeren beobachtet. Die Untersuchungen an den deuterierten Copolymeren zeigen, daß die Effekte der chemischen Gruppen bis zur dritten nach beiden Seiten vom markierten Methylen und die Stereokonfiguration von langen Vinyl-Chlorid-Anteilen betrachtet werden müssen, um die NMR-Spektren zu beschreiben. Die CCl₂-Gruppe läßt die chemische Verschiebung des Methylen-protons bei geringeren magnetischen Feldern und die CHCl-Gruppe bei höheren erscheinen.

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With 5 figures in 13 details and 4 tables     

Preparation of conjugates of peptides imitating part of the antigen-determinant section of protein VP1 of foot-and-mouth disease virus A12 with various supports

The preparation of conjugates of peptides 143–148, 153–159, 149–159, 146–159, and 143–159, imitating a section of a protein of the foot-and-mouth disease (FMD) virus of type A₁₂, with bovine serum albumin, with. a copolymer of N-vinylpyrrolidone with acrylic acid, and with a copolymer of N-vinylpyrrolidone with maleic anhydride is described. The dependence of the degree of conjugation on various factors is discussed.V. I. Lenin Tadzhik State University, Dushanbe. Institute of Immunology, Ministry of Public Health of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 516–519, July–August, 1990.     

ZnO nanorods decorated calcined Mg–Al layered double hydroxides as photocatalysts with a high adsorptive capacity

The nanocomposites of magnesium–aluminium–carbonate–layered double hydroxides (Mg–Al–CO₃–LDHs) and ZnO nanorods were prepared via a homogeneous precipitation process. The presence of ZnO nanorods made the calcined Mg–Al–CO₃–LDHs, the strong adsorptive adsorbents for anions, have a photocatalytic activity. Both Mg–Al–CO₃–LDHs and the nanocomposites with various ZnO/Mg–Al–CO₃–LDHs mass ratios from 0.5:1 to 3:1 were characterized by X-ray diffraction, transmission electron microscope and UV–vis diffuse reflectance spectra. The nanocomposites quickly adsorbed the anionic dyes such as acid red G (ARG) without the light illumination, and the adsorbed dyes on the recovered nanocomposites were then degraded in a separated photocatalytic reactor. The adsorption ability of the nanocomposites and their photocatalytic activities for the removal of ARG were evaluated by the Fourier transform infrared spectra and UV–vis extinction spectra. The sample at 3:1 ZnO/Mg–Al–CO₃–LDHs mass ratio was shown to have higher photocatalytic efficiencies.     

A study of the chemiluminescence behavior of myoglobin with luminol and its analytical applications

A chemiluminescence signal at 425 nm was observed when ferric state myoglobin was mixed with luminol in alkaline medium. Because the signal was remarkably enhanced in the presence of Fe(CN)₆ ^4–, analytical applications were investigated in a flow-injection system. The increase in chemiluminescence was linearly dependent on myoglobin concentration in the range 0.1 to 100 nmol L^–1, and the limit of detection was 0.04 nmol L^–1 with relative standard deviation 3.2% (3). It was also found that binding of Mb with the ligands CN^–, SCN^–, and F^– significantly inhibited the chemiluminescence reaction. The linear dynamic ranges for the ligands were 1.0–300.0, 0.1–3.0, and 0.5–100.0 nmol L^–1, and the limits of detection (S/N=3) 0.4, 0.04, and 0.2 nmol L^–1, for F^–, CN^–, and SCN^–, respectively. The relative standard deviations were 5.32%, 6.13%, and 3.38% for 0.1 nmol L^–1 CN^–, 0.5 nmol L^–1 SCN^–, and 1.0 nmol L^–1 F^–, respectively. At a flow rate of 2.0 mL min^–1 the assay could be accomplished in 1 min, including sampling and washing. The method has been successfully applied to the determination of myoglobin in human urine and F^– in water samples. A possible mechanism of chemiluminescence production by myoglobin and luminol is presented.     

Crystal Chemistry of Rare-Earth Chalcogenides

Crystal structures of Ln–X, Ln–Ln'–X, Ln–M–X, and Ln–X–Z compounds (Ln and Ln' are rare-earth elements; M is subgroup I–VIIIa or II–Vb cation and Z is subgroup V–VIIb anion; X is S, Se, or Te) were systematized and analyzed using data obtained by us and data from the literature. The structures of binary Ln–X chalcogenides can be divided into 4 groups: derivatives of NaCl-type structures, structures with one small parameter b 4 Å, structures similar to those of oxides and pniktides, and derivatives of PbFCl-type structures. Triple Ln–Ln'–X chalcogenides have structures similar to those of the binary chalcogenides of the first, second, and third groups. It was shown that the crystal structure of Ln–M–X depends on the size of cation M, its formal charge, electronegativity value, and electronic structure. The crystal structures of the phases in the Ln–M–X and Ln–X–Z compounds were compared with binary chalcogenide structures. Different variants of structure characterization and their potentialities are considered. Special attention is given to the defect-containing and ordered structures and to elucidating the role of the cation and anion vacancies in the phase structures.     

Solvent extraction and separation of some lanthanides and americium by extraction chromatography in the system Aliquat-336 — LiNO3 and HNO3

Summary The liquid-liquid extraction of Nd, Eu, Ho, and Am nitrates by means of the radiotracer method in the system tri-caprylmonomethyl ammonium nitrate /Aliquat-336/ — lithium nitrate and nitric acid was investigated.The mixture of tracer quantities of Eu–Am, Nd–Pr, Sm–Pm, Gd–Eu, Er–Ho, Tm–Er, Yb–Tm, and Lu–Tm were separated by column partition chromatography.

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Lösungsmittelextraktion und Trennung einiger Lanthanide und Americium durch Extraktions-chromatographie im System Aliquat-336 — LiNO₃ und HNO₃

Zusammenfassung Es wurde die Flüssig-Flüssig-Extraktion von Nd-, Eu-, Ho- und Am-Nitraten mit Hilfe radioaktiver Markierung im System Tri-caprylmonomethyl-ammoniumnitrat-/Aliquat-336/-Lithiumnitrat und Salpetersäure untersucht.Die Markierungsgemische von Eu–Am, Nd–Pr, Sm–Pm, Gd–Eu, Er–Ho, Tm–Er, Yb–Tm und Lu–Tm wurden durch Säulen-Verteilungs-Chromatographie getrennt.

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Extraction par solvant et separation de quelques lanthanides et d'americium par chromatographie d'éxtraction dans le système «Aliquat-336, LiNO₃, HNO₃»

Sommaire On a étudié, au moyen de la méthode des radiotraceurs, l'éxtraction liquide-liquide de nitrates de Nd, Eu, Ho et Am dans le système «nitrate de tri-caprylmonométhyl ammonium [Aliquat-336], nitrate de lithium, acide nitrique».Les mélanges de Eu–Am, Nd–Pr, Sm–Pm, Gd–Eu, Er–Ho, Tm–Er, Yb–Tm et Lu–Tm à la dose des traceurs radioactifs, ont été résolus en leurs composants chromatographie de partage sur colonne.

     

Lithium complexes and the kinetics of interactions of zinc ions with tetra(N-methyl-4–pyridyl)porphyrins in basic solution

The acidity of the free base (H2–P(X)) forms of the tetra- (N-methyl-4–(3 or 2)pyridyl)porphyrins were studied in basic solutions at 25 C, I=0.50. Equilibrium constants for both the H2– P(X)=P(X)2–+2H+ and the Li++ P(X)2–=Li- P(X)– reactions are reported. Log (KS) values for the Mn++P(4)2–=M- P(4)(n–2) reactions are 2.6 for Li+, 17.6 for Cd2+, 17.8 for Pb2+, 19.6 for (OH)2Hg, 25.9 for Zn2+ and 19.6 for the formation of Hg2–P(4)2+. Zn(OH)3– shows similar kinetic reactivity with both H2–P(4) and P(4)2– to form Zn- P(4) and HO-Zn- P(4)–,whileZn(OH)42– is unreactive with either species. For Zn2+, Zn(OH)+ and Zn(OH)3– with H2–P(4) the relative kinetic order for this tetrapositive macrocycle was ca. 1:300:20,000, while the trend Zn(OH)+>Zn2+>Zn(OH)3– is the usual pattern for peripherally negatively charged porphyrins.     

Concentration of Cr,Fe, Co and Zn in some Nigerian food grains

Elemental analysis of some Nigerian grains for cobalt, zinc, iron, and chromium, was done by thermal NAA. The concentration of these essential trace elements were found as follows: rice /0.18–0.98 ppm Cr, 27–307 ppm Fe, 0.133–0.237 ppm Co, 12.4–17.8 ppm Zn/; soyabean /0.32–0.59 ppm Cr, 67–81 ppm Fe, 0.244–0.358 ppm Co, 42–45 ppm Zn/; maize /0.05–0.75 ppm Cr, 22.7–47.6 ppm Fe, 0.20–0.65 ppm Co, 15.8–33.4 ppm Zn/; ground-nut /0.22–2.02 ppm Cr, 27.2–34.8 ppm Fe, 0.08–1.73 ppm Co, 24.3–38.2 ppm Zn/. No pattern was established for the elemental concentration in the grain samples. The result obtained suggest that an average diet of these grains will provide an adequate concentration of these essential elements.