Coiled Column Research Articles

A Comparative Study of the Dynamic Fractionation of Rare-Earth Elements in Soils Using a Rotating Coiled Column and a Microcolumn

A Comparative Study of the Dynamic Fractionation of Rare-Earth Elements in Soils Using a Rotating Coiled Column and a Microcolumn

A Comparative Study of the Dynamic Fractionation of Rare-Earth Elements in Soils Using a Rotating Coiled Column and a Microcolumn

Rare earth elements (REEs) are currently used in fertilizers, but their behavior in the soil–plant system remains poorly studied. The assessment of the binding of REEs to various organomineral phases of soils remains an important task. Using soddy-podzolic soil and typical chernozem as examples, we performed a comparative study of the dynamic fractionation of REEs in a rotating coiled column (RCC) and a microcolumn (MC). We isolated the exchangeable fraction, specifically adsorbed fraction, and fractions bound to manganese oxides, bound to organic matter, and bound to amorphous and weakly crystallized iron and aluminum oxides using, 0.05 M Ca(NO3)2, 0.43 M CH3COOH, and a 0.1 M NH2OH·HCl solution (pH 3.6), a 0.1 M K4P2O7 solution (pH 11.0), and a 0.1 M (NH4)2C2O4 solution (pH 3.2), respectively. Concentrations of elements in the initial samples and eluate fractions were determined by atomic emission spectrometry and inductively coupled plasma mass spectrometry. The results suggest that the main extractable REE form (up to 40% of the total content) is provided by organometallic complexes extracted with a 0.1 M K4P2O7 solution. For chernozem (soils with a high content of organic matter), fractionation in the RCC and MC yielded comparable results. For soddy-podzolic soil, some differences were observed in the isolation of the first three fractions: exchangeable, specifically adsorbed, and bound to manganese oxides. Both RCC and MC can be successfully used for the dynamic fractionation of REE in soils; however, it is preferable to use an MC in analyzing many samples as a simpler and more affordable device.

Extraction Concentration of the Acid-Soluble Forms of Rare Earth Elements from Oils of the Volga-Ural Petroleum Province Using Rotating Coiled Columns

Extraction Concentration of the Acid-Soluble Forms of Rare Earth Elements from Oils of the Volga-Ural Petroleum Province Using Rotating Coiled Columns

Extraction concentrating of the acid-soluble forms of rare earth elements from oils of the Volga-Ural oil and gas province using rotating coiled columns

Trace elements in oils are the natural markers of the oil origin of and the mechanism of oil genesis. Direct determination of rare earth elements (REE) in crude oils is rather difficult due to their low concentrations (10–6 wt. %). Information about the forms of trace elements in oils is of particular interest. The goal of the study is determination of the content of acid-soluble forms of REE in oils from various fields of the Volga-Ural oil and gas province. Six samples of oils of heavy and medium density and viscosity were analyzed. Extraction of acid-soluble forms of REE was carried out using rotating coiled columns in 0.5 M aqueous solution of nitric acid. Toluene was used to dilute the oils up to the necessary values of the density and viscosity providing the possibility of extraction in the system aqueous acid solution – oil. The content of REE was determined by inductively coupled plasma mass spectrometry on an Agilent 7900 spectrometer. Their content in an acid-soluble form in oil samples under study ranged within 172 – 2173 ng/kg. Such a wide range of values is attributed to the difference in the geology and age of deposit formation. The highest content of acid-soluble forms of REE (2173 ng/kg) was observed in the oil sample from the Novo-Elkhovsky field, whereas the lowest value (172 ng/kg) was measured in the oil sample of the Pioneer field. It is shown that the content of acid-soluble forms of REE depends on tectonic zoning, productive horizons and layers, as well as on the physical and chemical properties of oils. The distribution of acid-soluble forms of light and heavy REE was evaluated. Most of the REE (75 – 99%) determined in the analyzed oil samples are light REE. It is noted that systematization of the data on the properties of oils, geological and geochemical characteristics of the deposits will provide reliable forecasting of the various forms of REE present in oils.

Countercurrent chromatography approach to palladium and platinum separation using aqueous biphasic system

For the first time, widespread aqueous biphasic polymer-salt extraction system was applied for selective separation of Pd(II) and Pt(IV) from chloride technological solutions by countercurrent chromatography using a rotating coiled column (an analog of centrifugal extractor). The principle novelty of the proposed approach is the possibility of multistage extraction process and the needlessness to add any specific reagents for targeted metal binding. The results showed that the use of poly(ethylene glycol)-1500 (PEG-1500) as a stationary phase allows 96–100% of both Pd(II) and Pt(IV) to be recovered from chloride solutions containing copper and nickel. To obtain individual solutions of targeted metals it is enough to change the composition of the salt-rich phase for stripping stage, in particular the salt concentration and pH value. The final purity of the targeted metal fractions obtained after their extraction from model technological solutions is ≥ 99.9%. The components of the aqueous biphasic system are recyclable, non-toxic, available, and widespread in laboratory and technology practice. A scheme of the multistage separation of platinum metals using a rotating coiled column is proposed.

Field-Flow Fractionation in a Rotating Coiled Column in the Development of Reference Samples of Natural Nanoparticles

Field-Flow Fractionation in a Rotating Coiled Column in the Development of Reference Samples of Natural Nanoparticles

Separation of Pt(IV), Pd(II), and Rh(III) from Chloride Solutions by Multistage Extraction Using Nitrogen-Containing Extractants

This article demonstrates possible separation of Pd(II), Pt(IV), and Rh(III) ions from chloride solutions by solvent extraction in rotating coiled columns (RCC). The most common reagents used for extraction of platinum metals were selected as extractants: trioctylamine (TOA), methyltrialkylammonium chloride (MTAA), tributyl phosphate (TBP), and relatively new reagent—N,N,N',N'-tetra-n-octyldiglycolamide (TODGA). The completeness of extraction of platinum metals from individual and mixed hydrochloric acid and chloride solutions has been analyzed as a function of the essence and concentration of extractant, acidity of the analyzed solutions, and other factors. Optimum conditions of quantitative extraction of the metals from model hydrochloric acid and chloride solutions into the extractant phase have been determined, including subsequent selective separation at the re-extraction stage. A flowchart has been proposed for multistage extraction of Pd(II), Pt(IV), and Rh(III) using 0.05 M MTAA solution in toluene as a stationary phase in RCC. The flowchart includes extraction of Pd(II) and Pt(IV) ions from the solution (0.1 M HCl + 30 g/L Cl–) into the organic phase upon simultaneous separation of Rh(III) remaining in the aqueous phase and consecutive re-extraction of Pd(II) and Pt(IV) from the organic phase using 0.01 M solution of thiourea in 0.1 M HCl and 1 M solution of thiourea in 0.5 M HCl, respectively. The flowchart has been verified for separation of platinum metals in the production process of preset composition. The degree of metal extraction after processing by 0.05 M solution of MTAA in in toluene and consecutive re-extraction by solutions of thiourea is 99.5% for rhodium(III), 99.9% for palladium(II), and 97.4% for platinum(IV). The extracted aqueous phases of rhodium and platinum after output from the column did not contain impurities of other platinum metals. In the aqueous fraction of palladium, the platinum content was 0.5%.

Study of the Mobility of Cerium Oxide Nanoparticles in Soil Using Dynamic Extraction in a Microcolumn and a Rotating Coiled Column

Currently, nanomaterials are widely used in various fields of human activity, which inevitably leads to their release into the environment, and soils are one of the main reservoirs for nanoparticles. As nanoparticles can be particularly toxic to living organisms, the development of new approaches to the assessment of their behavior and mobility in soils is an important task. In this paper, the analytical possibilities of the dynamic extraction of CeO2 nanoparticles in a microcolumn (MC) and a rotating coiled column (RCC) are studied to evaluate the behavior of nanoparticles in soil. Differential and integral elution curves of CeO2 nanoparticles from the soil were obtained based on the data of eluate analysis by inductively coupled plasma–mass spectrometry. After pumping 100 mL of water through a microcolumn and a rotating coiled column, 0.15 and 1.37 µg of CeO2 nanoparticles are leached from the soil, respectively, which is 0.2 and 1.6% of the nanoparticles introduced. The ratio of CeO2 nanoparticles and soil mineral particles is two times higher in the MC eluate. It is found that the rotating coiled column enables the estimation of nanoparticles maximum mobility of nanoparticles in soil because of the minimization of the effect of its structure on their transport. The microcolumn, preserving the soil structure, ensures the estimation of the mobility of nanoparticles in a real soil column most accurately. We also studied the effect of the modification of the surface of CeO2 nanoparticles with citric acid on their mobility in soil. CeO2 nanoparticles modified with citric acid have higher mobility in soil compared to unmodified nanoparticles.

SEPARATION OF P t (IV), P d (II) AND R h (III) FROM CHLORIDE SOLUTIONS BY MULTISTAGE SOLVENT EXTRACTION USING NITROGEN-CONTAINING EXTRACTANTS

The possibility of Pd (II), Pt (IV), and Rh (III) separation from chloride solutions by solvent extraction in rotating coiled columns (RCC) is demonstrated. The reagents most frequently used in extraction of platinum metals were selected as extractants: trioctylamine (TOA), methyltrialkylammonium chloride (MTAA), tributylphosphate (TBP), N, N, N',N'-tetra-re-octyldiglyTOlamide (TODGA). The completeness of extraction of the platinum group metals from individual and mixed hydrochloric acidic and chloride solutions was studied depending on the nature and concentration of the extractant, acidity of the test solutions and other factors. Optimal conditions for the quantitative extraction of metals from model hydrochloric acidic and chloride solutions and subsequent selective separation at the stripping stage are specified. A scheme of multistaged extraction separation of Pd (II), Pt (IV), and Rh (III) from chloride solutions using a 0.05 M solution of MTAA in toluene as a stationary phase in RCC is proposed. The scheme includes extraction of Pd (II) and Pt (IV) ions from a chloride solution (0, 1 M HCl + 30 g/liter NT) into the organic phase with simultaneous separation of Rh(III) remaining in the aqueous phase, and sequential stripping of Pd (II) and Pt (IV) from the organic phase with a 0.01 M solution of thiourea in 0.1 M HCl and a 1 M solution of thiourea in 0.5 M HCl, respectively. The scheme was tested in separation of the platinum group metals from the technological solution of a given composition. The degree of metal extraction with a 0.05 M MTAA solution in toluene and sequential stripping with thiourea solutions is 99.5% for Rh (III), 99.9% for Pd (II), and 97.4% for Pt (IV). The separated water fractions of rhodium and platinum after leaving the column did not contain impurities of other platinum metals whereas the water fraction of palladium contained 0.5% Pt.

Partition efficiencies of three different coiled columns for the coil satellite centrifuge at higher rotation speed combinations

The partition efficiencies of three different coiled columns, conventional multilayer coiled column, eccentric coiled column and toroidal coiled column, were evaluated by the separation of 4-methylumbelliferyl sugar derivatives using the coil satellite centrifuge (CSC) with an organic-aqueous two-phase solvent system composed of ethyl acetate/1-butanol/water. The CSC apparatus was reinforced the planet axis to maintain the stable satellite motion, which was completed by combining the rotation of three axes including the sun axis (the angular velocity, ω1), the planet axis (ω2) and the satellite axis (ω3) under the relation at ω1 = ω2 + ω3. In the present study, four different rotation speed combination types were used for the separation at the ratio (ω1, ω2, ω3) = I. (300, 150, 150), II. (300, 100, 200), III. (300, 147, 153) and IV. (300, 200, 100 rpm) under different revolution speeds of ω1 = 300, 400 and 500 rpm. In the conventional multilayer coiled column with the upper mobile phase, the rotation speed combination type II yielded the best peak resolution while the rotation speed combination types III and IV had extremely low stationary phase retention even at higher revolution speeds. This inconvenience was eliminated by using the eccentric and the toroidal coiled column. The rotation speed combination type II for the eccentric coiled column and the type IV for the toroidal coiled column produced the best separation in both the upper and the lower mobile phases among four different rotation speed combination types. The overall results indicated that better peak resolution was obtained by the eccentric coiled column than by the toroidal coiled column except for the separation with the upper mobile phase at the low revolution speed.

Assessment of elemental composition and properties of copper smelter-affected dust and its nano- and micron size fractions

A comprehensive approach has been developed to the assessment of composition and properties of atmospherically deposited dust in the area affected by a copper smelter. The approach is based on the analysis of initial dust samples, dynamic leaching of water soluble fractions in a rotating coiled column (RCC) followed by the determination of recovered elements and characterization of size, morphology and elemental composition of nano-, submicron, and micron par ticles of dust separated using field-flow fractionation in a RCC. Three separated size fractions of dust (<0.2, 0.2-2, and >2 μm) were characterized by static light scattering and scanning electron microscopy, whereupon the fractions were analyzed by ICP-AES and ICP-MS (after digestion). It has been evaluated that toxic elements, which are characteristics for copper smelter emissions (As, Cu, Zn), are accumulated in fraction >2 μm. At the same time, up to 2.4, 3.1, 8.2, 6.7 g/kg of As, Cu, Zn, Pb, correspondently, were found in nanoparticles (<0.2 μm). It has been also shown that some trace elements (Sn, Sb, Ag, Bi, and Tl) are accumulated in fraction <0.2, and their content in this fraction may be one order of magnitude higher than that in the fraction >2 μm, or the bulk sample. It may be assumed that Sn, Sb, Ag, Bi, Tl compounds are adsorbed onto the finest dust particles as compared to As, Cu, Zn compounds, which are directly emitted from the copper smelter as microparticles.

Unexpected behavior of Zn, Cd, Cu, and Pb in soils contaminated by ore processing after 70 years of burial

Heavy metals in contaminated ore processing areas present a risk of contamination of waters and life. Therefore, the most mobile fractions of metals, which can be evaluated by chemical extraction, require a special research attention. Classical reports using batchwise extraction methods are debatable in terms of real metal availability because naturally occurring processes are always dynamic. Therefore, here we used dynamic extraction in a rotating coiled column in order to mimic natural conditions. We studied Cu, Pb, Zn, and Cd in soils and sand wastes from a tungsten–molybdenum plant. Soils had been buried under tailing dumps during 70 years. Exchangeable and acid-soluble fractions were separated using 0.05 M Ca(NO3)2 and 0.43 M CH3COOH, respectively. Results show that mobility, availability, and vertical transport of metals are surprisingly different. Specifically, there is nearly no mobile exchangeable Zn in wastes, whereas all studied soil horizons are characterized by elevated Zn concentrations, up to 0.6 g/kg. Cd behaves like Zn. The concentration and mobility of Cu vary with depth. The upper humus horizon contains up to 2.1 g/kg of exchangeable Cu. The behavior of Pb is quite particular: soils are nearly free from lead, though its total concentration in wastes may reach 3.9 g/kg. To the best of our knowledge, such unusual variations in the behavior of heavy metals have not been reported before.

Comparative study of methods for evaluating the mobility of element species in contaminated soil and technogenic sand under batch and dynamic extraction

A comparative study of the batch and dynamic extraction methods used to evaluate the physicochemical “mobility” of element species in environmental samples was carried out using samples of contaminated soils and technogenic sands of the Dzhida Tungsten–Molybdenum Factory. In determining the total concentration of mobile species of Cu, Zn, Pb, Cd, Mn, and Mo, they were extracted with an acetate–ammonium buffer solution (pH 4.8) in the batch mode. Fractionation of the most mobile and environmentally relevant element species, that is, exchange and acid-soluble, was carried out in a dynamic extraction mode in a rotating coil column using calcium nitrate and acetic acid. Element concentrations in the initial samples and extracts were determined by inductively coupled plasma atomic emission spectrometry and mass spectrometry. It is shown that the concentrations of mobile species of Cd, Mn, and Mo, isolated with an acetate–ammonium buffer solution, correspond to the sum of these elements in the exchange and acid-soluble fractions, while the concentration of lead in the acetate–ammonium extract is 2–4 times higher. The convergence of the results of dynamic and batch extraction of copper and zinc depends on the type of sample: for sand, the results are in satisfactory agreement, while for soil, the concentration of copper and zinc in the acetate–ammonium extract is 2–4 times lower than their concentration in the exchange and acid-soluble forms. Nevertheless, the data obtained confirm that the conventional method of batch extraction with an acetate–ammonium buffer solution (pH 4.8) can be considered acceptable for the rapid assessment of the physicochemical mobility and potential bioavailability of elements in soil and technogenic sand. For a more detailed study of highly contaminated samples and the assessment of their danger to the environment, it is advisable to separate exchange and acid-soluble fractions.

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).

Methodology for separation and elemental analysis of volcanic ash nanoparticles

A methodology for separation, characterization, and quantitative elemental analysis of volcanic ash nanoparticles is proposed. A combination of field-flow fractionation in a rotating coiled column and membrane filtration is used in the isolation and separation of nanoparticles. The size and morphology of nanoparticles were studied by static light scattering and scanning electron microscopy. The concentration of major- and trace elements in the bulk sample and the separated fractions was determined by inductively coupled plasma atomic emission spectrometry and mass spectrometry. It is shown that the total concentrations of most elements in the ash sample are comparable to their average concentrations in the Earth’s crust. On the other side, in the fraction 50–100 nm, the concentrations of Ni, Zn, Ag, Sn, Sb, Pt, Tl, Pb, and Bi are one or two orders of magnitude higher than their total concentrations, which probably indicates the preconcentration of corresponding elements from volcanic gases by nanoparticles. In the fraction represented by water-soluble forms of elements and nanoparticles smaller than 50 nm, Cu, Zn, Pb, and several other elements are found; the partition of elements between the solution and solid phase (nanoparticles) is assessed. The proposed methodology requires further development and application to the analysis of volcanic ash from various regions of the Globe.

Study on the Elemental Composition of Environmental Nanoparticles Separated in a Rotating Coiled Column: How Hazardous May Be Urban Dust and Volcanic Ash

Study on the elemental composition of nanoparticles is of great importance due to their high mobility in the environment and ability to penetrate into human organism. A global aspect is the transport of nutrient and toxic elements with environmental nanoparticles, which can serve as a carrier for these elements. Nanoparticles in complex polydisperse environmental samples such as dust, volcanic ash, or soil may represent only about thousandths or less of bulk sample. Therefore, their recovery followed by quantitative determination of analytes is a difficult task. A novel technique, sedimentation field-flow fractionation in a rotating coiled column, was applied to the fractionation of urban dust and volcanic ash samples with water being used as a carrier fluid. nanoand submicron particles have been separated, weighted, characterized by electronic microscopy and static laser light scattering, and then quantitatively analyzed by ICP-AES and ICP-MS (after digestion). In urban street dust samples, the elements that may be of anthropogenic origin (Zn, Cr, Ni, Cu, Cd, Sn, Pb) were found to concentrate mainly in &lt;0.3 and 0.3-1 μm fractions. It has been shown that the concentrations of Cr, Ni, Zn, Pb, Sn in the finest fraction (&lt;0.3 μm) of street dust can be one order of magnitude higher than the concentrations of elements in bulk sample and coarse fractions. For volcanic ash samples, it has been evaluated that nanoparticles may concentrate potentially toxic elements of volcanic gases. The concentrations of Zn, Cu, Pb, Tl, Bi, Sn, As, Sb in the size fraction &lt;0.2 μm can be two orders of magnitude higher than the concentrations of these elements in bulk sample. Hence, measuring the total concentrations of elements in dust and ash leads to underestimation of the hazard of these samples. The proposed approach to the separation and quantitative analysis of environmental nanoparticles can be a powerful tool for risk assessment related to toxic elements in dust, ash, and other particulate matter.

Comparison of the peak resolution and the stationary phase retention between the satellite and the planetary motions using the coil satellite centrifuge with counter-current chromatographic separation of 4-methylumbelliferyl sugar derivatives

Coil satellite centrifuge (CSC) produces the complex satellite motion consisting of the triplicate rotation of the coiled column around three axes including the sun axis (the angular velocity, ω1), the planet axis (ω2) and the satellite axis (the central axis of the column) (ω3) according to the following formula: ω1=ω2+ω3. Improved peak resolution in the separation of 4-methylumbelliferyl sugar derivatives was achieved using the conventional multilayer coiled columns with ethyl acetate/1-butanol/water (3: 2: 5, v/v) for the lower mobile phase at the combination of the rotation speeds (ω1, ω2, ω3)=(300, 150, 150rpm), and (1:4:5, v/v) for the upper mobile phase at (300:100:200rpm).The effect of the satellite motion on the peak resolution and the stationary phase retention was evaluated by each CSC separation with the different rotation speeds of ω2 and ω3 under the constant revolution speed at ω1=300rpm. With the lower mobile phase, almost constant peak resolution and stationary phase retention were yielded regardless of the change of ω2 and ω3, while with the upper mobile phase these two values were sensitively varied according to the different combination of ω2 and ω3. For example, when ω2=147 or 200rpm is used, no stationary phase was retained in the coiled column while ω2=150rpm could retain enough volume of stationary phase for separation. On the other hand, the combined rotation speeds at (ω1, ω2, ω3)=(300, 300, 0rpm) or (300, 0, 300rpm) produced insufficient peak resolution regardless of the choice of the mobile phase apparently due to the lack of rotation speed except at (300, 0, 300rpm) with the upper mobile phase. At lower rotation speed of ω1=300rpm, better peak resolution and stationary phase retention were obtained by the satellite motion (ω3) than by the planetary motion (ω2), or ω3>ω2.The effect of the hydrophobicity of the two-phase solvent systems on the stationary phase retention was further examined using the n-hexane/ethyl acetate/1-butanol/methanol/water system at different volume ratios. In the satellite motion at (ω1, ω2, ω3)=(300, 150, 150rpm), almost constant stationary phase retention was obtained with the lower mobile phase regardless of the hydrophobicity of the solvent system whereas the stationary phase retention varied according to the volume ratio of the two-phase solvent system for the upper mobile phase. However, stable stationary phase retention was observed with either phase used as the mobile phase.In order to analyze the acceleration acting on the coiled column, an acceleration sensor was set on the column holder by displacing the multilayer column. The combination of the rotation speeds at (300, 100, 200rpm) showed double loops in the acceleration track, whereas (300, 150, 150rpm) showed a single loop, and all other combinations showed, complex tracks.The overall results indicate that the satellite motion is seriously affected by the combination of rotation speeds and the hydrophobicity of the two-phase solvent system when the upper phase was used as the mobile phase for separation.

A set of analytical methods for the estimation of elemental and grain-size composition of volcanic ash

A combined approach to the analysis of volcanic ash (VA) was proposed. Ash particles were separated by size using a combination of vibration sieving on sieves (140, 70, 40 μm) and field-flow fractionation in a rotating coiled column (for separation of nano- and submicron particles). Initial samples and obtained fractions were characterized using scanning electron microscopy and static light scattering. Their elemental composition was determined using ICP-MS and ICP-AES methods. The radionuclide composition of the VA was studied by the low-background gamma spectrometry. The studies were carried out by the example of ashes from Puyehue volcano, the Puyehue Cordon Caulle volcanic group, Andes (Santiago, eruption on June, 2011), which were taken immediately after eruption and after first rain. It was shown that up to 15% of major elements (such as P, Ca, and К) and trace elements (such as Be, Hg, Tl, As, Sb, and Bi) could be extracted from the ash by rain and migrate into environment. It was also found that the content of radionuclides (U235, Th234, Pb214, Bi214, Be7) after rain decreases by 30–40%. Of special interest are ash nanoparticles (up to 200 nm), in which the contents of Cu, Pb, Tl, Bi, Sn, As, and Sb are over an order of magnitude higher than the bulk contents of these elements in the ash. This regularity was found in samples taken both prior to and after rain. The proposed methodology of fractionation, study, and analysis of ash particles may be applied for a wide range of soil, ash, and dust samples of different nature.

A combined method of sample preparation for the determination of the total element composition of oils

A comprehensive approach to the determination of the elemental composition of oils (including those with a viscosity of 5000 mm2/s) is proposed. It ensures the determination of the most elements present in oils using two versions of sample preparation, autoclave decomposition of oil samples and extraction preconcentration of elements from oil into an aqueous solution on rotating coiled columns (RCCs). The application of RCCs in the elemental analysis of oil ensures the preconcentration of a number of trace elements from oil (including rare-earth elements) and the determination of their concentrations at a level of ng/kg. The preconcentration factor of trace elements from oil using an RCC depends on the volume of oil sample pumped through a constant volume of the stationary phase (acid solution) retained in the column and on the speciation of elements in the oil.

Improved Separations of Proteins and Sugar Derivatives Using the Small-Scale Cross-Axis Coil Planet Centrifuge with Locular Multilayer Coiled Columns.

Countercurrent chromatography (CCC) is liquid-liquid partition chromatography without using a solid support matrix. This technique requires further improvement of partition efficiency and shortening theseparation time. The locular multilayer coils modified with and without mixer glass beads were developed for the separation of proteins and 4-methylumbelliferyl (MU) sugar derivatives using the small-scale cross-axis coil planet centrifuge. Proteins were well separated from each other and the separation was improved at a low flow rate of the mobile phase. On the other hand, 4-MU sugar derivatives were sufficiently resolved with short separation time at a highflow rate of the mobile phase under satisfactory stationary phase retention. Effective separations were achieved using the locular multilayer coil for proteins with aqueous-aqueous polymer phase systems and for 4-MU sugar derivatives with organic-aqueous two-phase solvent systems by inserting a glass bead into each locule.