On the Use of Indium Arsenide as the Waveguide Material in the Measurements by Attenuated Total Reflectance

Optics and Spectroscopy - The current–voltage characteristics and photocurrent of “monolithic” diode optical pairs optically coupled by a substrate made of InAs common for them...     

Chemical analysis of rain and snow samples from Chernogolovk/Russia by IC, TXRF and ICP–MS

 Data are reported for a first measurement campaign for a great number of cations (the range of concentrations for main components is given in ng/mL: Na:<70–880; Mg: 12–160; Al:<7–120; K: 200–1600; NH₄ ⁺: 2500–9000; Ca: 300–2500; Fe:<140–1200; Zn: 20–320) and anions (HCOO^-: 100–1800; CH₃COO^-: 400–14500; C₂O^2- ₄: <100–460; NO^- ₂: <20–55; NO^- ₃: 660–9900; SO^2- ₃:<100–1150; SO₄ ^2-: 450–19700; Cl^-: 170–3200) in rain and snow samples of the Chernogolovka region 80 km northeast of the centre of Moscow. These data serve as a first assessment of the situation of the atmosphere in this region. For the determination of fluoride, formate, acetate, nitrite, bromide, nitrate, sulfite, and sulfate by IC, a relevant development of the method was carried out. For some metallic cations, a critical quality control was achieved by parallel measurements with ICP-MS, TXRF, and IC. Furthermore, time resolved measurements were performed for a rain event. Filtration experiments were undertaken to differentiate between the presence of a series of elements and species in liquid or solid state in the collected aqueous samples. Received: 25 July 1996 / Revised: 26 September 1996 / Accepted: 13 October 1996     

Application of Rotating Coiled Columns to the Fractionation of Soil Particles and to the Sequential Extraction of Heavy-Metal Species from Silty,Dusty, and Sandy Fractions

A complex procedure has been developed for evaluating the degree of soil contamination. Rotating coiled columns (RCCs) were used for both the fractionation of soil samples by their grain-size composition and the sequential extraction of heavy-metal species from silty, dusty, and sandy fractions. During the extraction of heavy-metal species, the soil fraction to be analyzed was retained in the column as a stationary phase, while aqueous solutions of extracting agents (mineral salts, acids, and complexing compounds) were sequentially pumped through the heterogeneous sample. The sequential extraction of element species from various soil fractions was carried out in the dynamic mode favorable to more complete extraction of metals. The use of RCCs allows the extraction of various heavy-metal species from soils to be performed in accordance with their grain-size composition. The process of the extraction of metal species can be automated, and in this case the losses of sample components are reduced to a minimum.__________Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 7, 2005, pp. 765–772.Original Russian Text Copyright © 2005 by Katasonova, Fedotov, Karandashev, Spivakov.     

Extraction Properties of Oligodentate Carbamoylmethylphosphine Oxides and β-Aminophosphine Oxides Toward Lanthanides and Rhenium(VII)

Abstract

The extraction properties of a series of carbamoylmethylphosphine oxides and β-aminophosphine oxides with lanthanide metal ions is presented. Tris[bis(2-diphenyl- phosphorylethyl)-aminoethyl]amine is shown to be highly effective for extraction of Re(VII).     

Effect of Phosphonium Ionic Liquids on the Extraction of Rare-Earth Elements(III) with 2,2′-Oxybis(N,N-dioctylacetamide) from Nitric Acid Solutions

Russian Journal of General Chemistry - New phosphonium ionic liquids, alkyldiphenylethylphosphonium bis[(trifluoromethyl)sulfonyl]imides (Alk = C4H9, C8H17, and C12H25) have been synthesized. The...     

Strong instability of the minima spectrum of a quadratic binary functional

Doklady Mathematics -     

Estimation of the effect of thermal and resonance neutron shielding in activation analysis

A semiempirical method of allowing for the effect of impurity element screening in samples of irregular geometry, absorbing thermal and resonance neutrons, is suggested. The accuracy of this method was evaluated for cobalt, silver, indium, iridium, gold and mercury and experimentally checked for silver and indium samples.     

Isolation and quantitative analysis of road dust nanoparticles

Nanoparticles are capable of preconcentrating various elements, including toxic ones; they have high mobility in the environment and can easily penetrate into a human body. The study of the chemical composition and properties of road dust nanoparticles is an urgent task of analytical chemistry, which needs to be addressed in the monitoring of the anthropogenic load on the environment and the assessment of the potential danger of pollution to human health. In the present paper, we propose a new approach for the isolation, characterization, and quantitative elemental analysis of road dust nanoparticles. Conditions are selected for the separation of nanoparticles from Moscow dust samples by field-flow fractionation in a rotating coiled column; the resulting fractions are characterized by independent methods (using static light scattering and electron microscopy); the method for calculating the concentration of elements in the nanoparticle fraction according to inductively coupled plasma atomic emission spectrometry and mass spectrometry is improved; elements in a water-soluble form are isolated and determined; and the role of soluble organic matter in the binding of trace elements is discussed. It is shown that the total concentration of most elements in the samples of Moscow dust is comparable to the average values for urban soils. Abnormally high concentrations of several elements (Cu, Zn, Ag, Cd, Sn, Sb, Hg, Pb, Tl, and Bi) are revealed in the fraction of nanoparticles; the enrichment factor with respect to the total concentration ranges from 10 to 450. The source of contamination of road dust nanoparticles with copper, zinc, antimony, and cadmium is highly probable wearing-off of brake pads and car tires. The developed procedure of separation, characterization, and analysis of nanoparticles can be used for other polydisperse environmental samples (for example, volcanic ash).     

Extraction of scandium and rare-earth elements by a phosphorylated azapodand

The interphase distribution of microamounts of nitrates and perchlorates of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu between aqueous solutions of NH₄NO₃ or NH₄ClO₄ and solutions of a phosphorylated podand [Ph₂P(O)CH₂CH₂OCH₂CH₂]₂NBu in dichloroethane was studied. The stoichiometry of extracted complexes was determined. The efficiency of metal ion transfer to an organic phase was considered as affected by HClO₄, HNO₃, and HCl concentrations in the aqueous phase and by the nature of the organic solvent. The test compounds have higher extraction capacities with respect to metal ions than neutral monodentate organophosphorus compounds.