D. G. Filatova

Determination of gallium in biological fluids using inductively coupled plasma mass spectrometry

A procedure for the determination of gallium in biological fluids by inductively coupled plasma mass spectrometry was developed. The detection limits of gallium calculated from the 3s value were 60 ng/L for urine, 32 ng/L for a model solution of intestinal juice, and 50 ng/L for serum. The accuracy of the procedure was tested using a standard addition method. The nature of a background signal on the masses of gallium isotopes was studied with the use of a high-resolution mass spectrometer, and the background concentration of gallium in biological fluids was evaluated (5–7 ng/L). It was found that a background level in measurements performed on a quadrupole mass spectrometer depends on the interfering influence of polyatomic ions with close m/z ratios rather than on the background concentration of gallium. The procedure makes it possible to study the stability of pharmaceutical preparations based on gallium in biological media, their metabolism, and the excretion of preparations from the body.

Direct atomic-absorption determination of platinum, palladium, and rhodium in dead ceramic-based autocatalysts

The data on the effect of different concentrations of components of dead automobile catalysts on determination of platinum, palladium, and rhodium using the method of ETAAS are obtained and systematized. The conditions for direct atomic-absorption determination of Pt, Pd, and Rh are optimized. The technique of atomic-absorption determination of PM in secondary raw and technogenic materials is developed (n × 10−4−n × 10−1 wt %, sr = 0.12–0.07).

Sorption-atomic-absorption determination of platinum, palladium, and rhodium in dead autocatalysts

The conditions for determination and group concentration of platinum metals (PMs) in the presence of matrix components using new S,N-containing complex-forming sorbents in solutions obtained after decomposition of decontaminated autocatalysts are proposed. The technique of atomic-absorption determination of PMs from a solution (n × 10−4−n × 10−2; sr = 0.15–0.07) and a solid phase (n × 10−5−n × 10−4; sr= 0.20–0.12) is developed.

SnO2(Au0, CoII, III) nanocomposites: A synergistic effect of the modifiers in CO detection

Nanocrystalline SnO2 has been synthesized and its surface has been modified with Au0 and Co(II, III). The distribution of the modifiers over the nanocomposites has been studied by X-ray diffraction, inductively coupled plasma mass spectrometry, and transmission electron microscopy. The effect of the modifiers on the hydrogen reduction of nanocrystalline SnO2 has been assessed. The CO sensing properties of the synthesized materials (10 ppm CO in air) have been studied in situ by electrical conductance measurements. The addition of both Au0 and Co(II, III) allows the working temperature of the SnO2-based semiconductor sensor to be lowered to 215°C.

Spectrophotometric and Fluorimetric Determination of Amino Acids by Their Reaction with o-Phthalic Aldehyde in the Presence of Sulfite and Cyanide Ions

Optimum conditions were selected for the determination of amino acids by their reaction with o-phthalic aldehyde in the presence of sodium sulfite and potassium cyanide using glycine as an example. It was shown that the analytical characteristics of the proposed procedure are highly competitive with those of a widely employed procedure using 2-mercaptoethanol and that the stability of the analytical form (substituted isoindols) was much higher.

Determination of selenium and cadmium dopants in nanocomposites based on zinc and indium oxides by high resolution continuous source electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry

An approach is proposed to the determination of selenium and cadmium dopants in new nanocomposites based on zinc and indium oxides. The approach is based on a combination of highly efficient high resolution continuous source electrothermal atomic absorption spectrometry (ETAAS) for the analysis of suspensions and inductively coupled plasma mass spectrometry for the analysis of solutions. A procedure is developed for the determination of Se and Cd dopants and matrix components based on Zn and In in nanocomposite solutions by inductively coupled plasma mass spectrometry. Stabilizing agents for the preparation of suspensions are studied for the ETAAS analysis of powders without their decomposition. The results of determination of CdSe dopants by high resolution ETAAS are validated by inductively coupled plasma mass spectrometry.

Effect of heterovalent substitution on the electrical and optical properties of ZnO(M) thin films (M = Ga, In)

Films of undoped ZnO and zinc oxide doped with gallium and indium (ZnO(Ga) and ZnO(In)) have been prepared by the spin-coating method with the subsequent annealing at 500°C. Phase composition, microstructure, conductivity, and optical properties of the films have been investigated depending on the content of gallium and indium in them.

Effect of Ga and in doping on acid centers and oxygen chemisorption on the surface of nanocrystalline ZnO

Nanocrystalline gallium- and indium-doped zinc oxide samples have been prepared through coprecipitation from aqueous solutions. Acid centers on the surface of the materials have been investigated using temperature-programmed desorption and IR spectroscopy. The results demonstrate that, with increasing dopant concentration, the density of OH groups on the surface of ZnO〈Ga〉 and ZnO〈In〉 increases and the contribution of cation centers to surface acidity decreases. The interaction of the material with oxygen has been studied using in situ electrical conductivity measurements. Doping of zinc oxide with gallium or indium has been shown to increase the percentage of molecular chemisorbed oxygen species on the surface of the material.

Determination of arsenic, cadmium, selenium, and tellurium in technogenic raw materials after sorption concentration on hydroxides using inductively coupled plasma atomic emission spectrometry

A method of group extraction of As, Se, Te, and Cd using hydroxides of iron, lanthanum, and magnesium in analysis of technogenic raw materials which makes it possible to simplify determination of the listed elements and to consider and reduce possible interferences is proposed. On the basis of the performed studies, an ICP-AES express method of determination of toxic elements in technogenic copper-containing raw material is developed. The relative standard deviation of the results of analysis performed using the developed method is 9–2.5% at concentrations of the determined elements from n × 10−4 to n × 10−1 wt %.

Determination of antimony and tin in tin dioxide whiskers by inductively coupled plasma mass spectrometry

A procedure for the determination of antimony and tin in tin dioxide whiskers, which were grown from a gas phase by the vapor-liquid-solid mechanism, was developed. The problem was difficult because the single whiskers are irregularly small in size and have a small weight (about 10−5 g). The procedure is based on the decomposition of a solid sample by cementation on zinc followed by the determination of analytes with the use of inductively coupled plasma mass spectrometry. The procedure developed is characterized by the detection limits of antimony of 0.01–0.03 μg/L and an RSD of 10%. An approach was proposed to estimate the antimony content of single whiskers.