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The study of the properties and composition of natural nanoparticles is an essential problem in analytical chemistry. Currently, there are no reference samples of natural nanoparticles, which complicates the study of the role of nanoparticles in specific processes, including geochemical ones, and makes it almost impossible to compare the results obtained by different researchers. In this work, nanoparticles of kaolinite, montmorillonite, and muscovite are studied as potential reference samples of natural nanoparticles. A complex of analytical methods has been proposed for the isolation and characterization of mineral nanoparticles, including the field flow fractionation of particles in a rotating coiled column, laser diffraction, scanning electron microscopy, and inductively coupled plasma atomic emission spectrometry. According to laser diffraction data, 93–98% of the isolated particles are from 40 to 300 nm in size; 2–7% of particles have sizes of up to 830 nm. The sizes of the isolated particles were confirmed by scanning electron microscopy. Based on the aluminum content, the concentrations of mineral nanoparticles in the isolated suspensions were estimated. The aggregation stability of nanoparticles in 5 mM phosphate buffer solutions of pH 6, 7, and 8 was studied. Muscovite nanoparticles are stable at pH 7 and 8 for at least 4 weeks, while montmorillonite nanoparticles have similar stability only at pH 8. For kaolinite nanoparticles, significant aggregation was observed at all studied pH values of buffer solutions. The obtained experimental results made it possible to clarify the problems and assess the prospects for developing reference samples of natural nanoparticles.

Natural nanomaterials, which play a very important role in environmental processes, are so far poorly studied. Firstly, the separation of nanoparticles from the bulk sample is a challenge. Secondly, the absence of reference natural nanomaterials makes it impossible to compare the results obtained by different researchers and develop a unified methodology for the separation and characterization of natural nanomaterials. Therefore, the development of reference natural nanomaterials is an urgent need of the environmental analytical chemistry. In this work, mineral nanoparticles (kaolinite, montmorillonite, muscovite, and quartz) have been studied as potential reference natural nanomaterials. A set of analytical methods including coiled-tube field-flow fractionation, scanning electron microscopy, dynamic light scattering, laser diffraction, inductively coupled plasma atomic emission, and mass spectrometry are applied to the separation and characterization of nanoparticles. It has been shown by laser diffraction that 93–98% of separated mineral nanoparticles are in the size range from about 40 to 300 nm, while 2–7% have size up to 830 nm. The size range of particles is confirmed by electron microscopy. Major (Al, Na, K, Ca, Fe), trace (Ti, Co, Cu, Zn, Tl, Pb, Bi, etc.), and rare earth elements have been determined in the suspensions of kaolinite, montmorillonite, and muscovite nanoparticles. Based on Al content, the concentration of mineral nanoparticles in suspensions is estimated. Agglomeration stability (consistency of size distribution) of nanoparticles at pH 6–8 is assessed. It has been shown that muscovite nanoparticles are stable at pH 7–8, whereas montmorillonite nanoparticles are stable only at pH 8 for at least 4 weeks. A noticeable agglomeration of kaolinite nanoparticles is observed at pH 6–8. Due to the low concentration of quartz nanoparticles, their characterization and stability assessment are hindered. The challenges of the development of reference natural nanomaterials are discussed.

Nanoparticles are a potential source and carrier of nutrients and pollutants in aquatic ecosystems, yet the stability of nanoparticles in environmental conditions is poorly known. Here, we studied volcanic ash nanoparticles by simultaneous application of capillary zone electrophoresis and laser diffraction for determination of size, zeta-potential and long-term aggregation stability. Results show that volcanic ash nanoparticles remained stable for at least 28 days. Stability increases from pH 5.5 to 8.5. Zeta-potentials are − 56 mV at pH 7.2 and − 64 mV at pH 8.5. Findings imply that volcanic ash nanoparticles have a high potential for long-range transport of nutrient and toxic elements in surface waters. Moreover, the developed method allows direct conversion of electropherograms into particle size distributions.

The study and analysis of dust nano- and microparticles are necessary in the estimation of anthropogenic load on the environment and the determination of the sources of pollution in urban ecosystems. In this work, an approach based on a multistage membrane filtration method is proposed for assessing the contribution of a metallurgical enterprise to the pollution of nano- and microparticles in urban dust. The contribution of an aluminum smelter to dust pollution in Kandalaksha was estimated. The elemental composition of the initial dust samples was studied. The fractions of dust particles with sizes of

An advantage of using capillary zone electrophoresis and static light scattering is demonstrated on an example of suspensions containing nano- and submicroparticles of volcanic ash under the condition of simultaneous studies using the same aqueous suspensions. We found the dependences of the electrophoretic mobility and the zeta potential of nano- and submicroparticles on size by comparing electropherograms with diagrams of size distributions. These dependences can be used for the satisfactory estimation of weight-average particles size in the newly prepared suspensions.

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.

Nowadays, widespread application of engineered nanoparticles (ENPs) inevitably leads to their release into the environment. Soils are regarded as the ultimate sink for ENPs. The study on mobility of ENPs in soils is important in the assessment of potential risks related to their toxicity. The behavior of ENPs is dependent not only on parameters of soil but also on exposure scenarios, namely, the amount of ENPs trapped in soil. In the present work, the mobility of cerium dioxide nanoparticles (nCeO2) in soils at different exposure scenarios has been studied. The relationship between mobility of nCeO2 and their concentration in soil in the range from 1 to 1000 μg g−1 is evaluated. It is shown that the mobility of nCeO2 decreases with decreasing their concentration in soil and attains the minimum value at the concentration of nCeO2 below 10 μg g−1. In relative terms, only about 0.1–0.2% of nCeO2 at their concentration in soil 10–1000 μg g−1 are mobile and can migrate in soil profile under saturated conditions. The major portion of nCeO2 (about 99.8%) remains immobile in soil. Evidently, the vertical transport of nCeO2 in soil profile should depend on volume of released suspensions. In the case of small or moderate wet deposition, nanoparticles will accumulate in upper soil horizons, where biological activity is highest, and affect the soil inhabitants (plant roots, earthworms, insects, microorganisms, etc.).

International audience; In the present work, major and trace element concentrations in suspensions of volcanic ash nanoparticles were determined by ICP-MS after either the acid digestion of the suspensions or the direct analysis of these suspensions. The results obtained were compared. Since the acid digestion can be accompanied by an important dilution or can consist in different steps of evaporation and dilution, the determination of some trace element concentrations became limited because of the limit of detection of the analytical instrument. Therefore, analysis after acid digestion of suspensions and direct analysis after acidification of these suspensions were carried out and compared. The concentration of Al, Fe, Y, La, Ce, Pr, Gd, Ho, Cu, Tl and Pb determined by both preparation procedures were in agreement. The values of relative standard deviation are in the range from 1% to 14%. These results prove the reliability of the direct ICP-MS analysis and the possibility of its further application in hyphenated systems for the dimensional and elemental characterisation of natural mineral nanoparticles

Natural nanomaterials, which play a very important role in environmental processes, are so far poorly studied. Firstly, the separation of nanoparticles from the bulk sample is a challenge. Secondly, the absence of reference natural nanomaterials makes it impossible to compare the results obtained by different researchers and develop a unified methodology for the separation and characterization of natural nanomaterials. Therefore, the development of reference natural nanomaterials is an urgent need of the environmental analytical chemistry. In this work, mineral nanoparticles (kaolinite, montmorillonite, muscovite, and quartz) have been studied as potential reference natural nanomaterials. A set of analytical methods including coiled-tube field-flow fractionation, scanning electron microscopy, dynamic light scattering, laser diffraction, inductively coupled plasma atomic emission, and mass spectrometry are applied to the separation and characterization of nanoparticles. It has been shown by laser diffraction that 93-98% of separated mineral nanoparticles are in the size range from about 40 to 300 nm, while 2-7% have size up to 830 nm. The size range of particles is confirmed by electron microscopy. Major (Al, Na, K, Ca, Fe), trace (Ti, Co, Cu, Zn, Tl, Pb, Bi, etc.), and rare earth elements have been determined in the suspensions of kaolinite, montmorillonite, and muscovite nanoparticles. Based on Al content, the concentration of mineral nanoparticles in suspensions is estimated. Agglomeration stability (consistency of size distribution) of nanoparticles at pH 6-8 is assessed. It has been shown that muscovite nanoparticles are stable at pH 7-8, whereas montmorillonite nanoparticles are stable only at pH 8 for at least 4 weeks. A noticeable agglomeration of kaolinite nanoparticles is observed at pH 6-8. Due to the low concentration of quartz nanoparticles, their characterization and stability assessment are hindered. The challenges of the development of reference natural nanomaterials are discussed.

The waste stream of obsolete electronic equipment grows exponentially, creating a worldwide pollution and resource problem. Electrical and electronic waste (e-waste) comprises a heterogeneous mix of glass, plastics (including flame retardants and other additives), metals (including rare Earth elements), and metalloids. The e-waste issue is complex and multi-faceted. In examining the different aspects of e-waste, informal recycling in developing countries has been identified as a primary concern, due to widespread illegal shipments; weak environmental, as well as health and safety, regulations; lack of technology; and inadequate waste treatment structure. For example, Nigeria, Ghana, India, Pakistan, and China have all been identified as hotspots for the disposal of e-waste. This article presents a critical examination on the chemical nature of e-waste and the resulting environmental impacts on, for example, microbial biodiversity, flora, and fauna in e-waste recycling sites around the world. It highlights the different types of risk assessment approaches required when evaluating the ecological impact of e-waste. Additionally, it presents examples of chemistry playing a role in potential solutions. The information presented here will be informative to relevant stakeholders seeking to devise integrated management strategies to tackle this global environmental concern.

Volcanic activity is one of the main sources of natural nanoparticles. It has been found earlier that the concentration of toxic metals/metalloids in nanoparticles of volcanic ash may be one or two orders of magnitude higher than in bulk sample. However, fate and behavior of toxic metals/metalloids depend on the type of their binding to nanoparticles. Hence, element species adsorbed onto pyroclastic nanoparticles and individual nanophases of metal/metalloid oxides or salts should be distinguished. For the first time, the single particle inductively coupled plasma mass spectrometry has been applied to the nanospeciation of volcanic particles. Ashes of four volcanoes of Kamchatka (Russia) were under study. Nanoparticles were separated from bulk ash samples using coiled-tube field-flow fractionation. It has been shown that the nanospeciation of Ni, Zn, Ag, Cd, Tl, As, Pb, Bi, Te, and Hg is dependent on element and volcano. In most cases these elements can be found both as species absorbed onto pyroclastic nanoparticles and as individual nanophases. The ratios of individual nanophases and adsorbed species vary with the sample. In nanoparticles of Tolbachik volcano ash, Ni, Zn, Tl, and Hg are present only as individual nanophases, while Bi, As, Pb, Ag, Cd, and Te are found both as adsorbed species and individual nanophases. The results obtained open a new door into study on the chemical composition of volcanic ash nanoparticles and their fate in the environment.

International audience; Theoretical background, instrumentation, and applications of “conventional” sedimentation field-flow fractionation in thin channels (SdFFF) and “non-conventional” sedimentation coiled-tube field-flow fractionation (CTFFF) in rotating columns are summarized and compared. Applications are classified into three main groups: environmental studies, material science, and biological studies. SdFFF is a versatile separation and sizing method applicable to complex particulate matter such as environmental samples, engineered particles, cells, etc. However, the mass of injected particles does not usually exceed 10–20 µg to avoid overloading. CTFFF enables the mass of the particulate sample to be increased up to grams. Despite its low resolution as compared to SdFFF, CTFFF has important niche applications. It opens a new door into the isolation of nano- and submicron particles from bulk samples of different origin and nature. In addition, CTFFF is a very promising instrument for the separation and purification of nano- and microparticles at preparative and even industrial scale. Abbreviations: A4F–Asymmetrical flow field-flow fractionation; CSF–Conventional SPLITT fractionation; CTFFF–Coiled-tube field-flow fractionation; CV-ETAAS–Cold vapor electrothermal atomic absorption spectroscopy; DLS–Dynamic light scattering; EDS–Energy dispersive X-ray spectroscopy; ES-SMPS–Electrospray-scanning mobility particle sizer; ETAAS–Electrothermal atomic absorption spectroscopy; FE–Fractionation efficiency; FFDSF–Full feed depletion SPLITT fractionation; FFF–Field-flow fractionation; ICP-AES–Inductively coupled plasma-atomic emission spectrometry; ICP-MS–Inductively coupled plasma-mass spectrometry; LD–Laser diffraction; MAD–Monoolein aqueous dispersions; MALS–Multi-angle light scattering; NLC–Nanostructured lipid carriers; NP–Nanoparticle; NTA–Nanoparticle tracking analysis; OM–Optical microscopy; PS–Polystyrene; PSD–Particle size distribution; RCC–Rotating coiled column; SdFFF–Sedimentation field-flow fractionation in thin channels; SEM–Scanning electron microscopy; SP-ICP-MS–Single-particle inductively coupled plasma-mass spectrometry; SPLITT–Split-flow thin-cell fractionation; TEM–Transmission electron microscopy; UV–Ultraviolet detector.

At present, there is concern about engineered nanoparticles in the environment, whereas natural nanoparticles (NPs) and their impact are often neglected. In our paper, we demonstrate the important role of nanoparticles of volcanic ash in transport of toxic elements on a global scale. A single volcanic eruption can eject millions of tons of ash. NPs of volcanic ash reach the upper troposphere and the stratosphere and may "travel" around the world for years affecting human health, environment, and even climate. So far, there is a gap in exposure assessment of volcanic ash NPs since their chemical composition remains largely unknown. Here we show for the first time that volcanic ash NPs can serve as an important carrier for potentially toxic elements. The concentrations of Ni, Zn, Cd, Ag, Sn, Se, Te, Hg, Tl, Pb, Bi in volcanic ash NPs (

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).

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

Study on the behavior and fate of nanofertilizers in soil plays a key role in the assessment of the efficiency of their use for intended purposes. The behavior of nanoparticles (NPs) in soil depends on environmental scenarios, such as Wetting-Drying cycles (WDCs). In the present work, the mobility and fate of CeO2, ZnO, and Cu NPs in agricultural soil at sequential WDCs have been studied. It has been shown that the mobility of CeO2 and ZnO NPs decreases after each WDC. After four WDCs the relative amount of CeO2 and ZnO NPs leached from soil decreases from 0.11 to 0.07% and from 0.21 to 0.07%, correspondingly. The decrease in the mobility of NPs is caused by their immobilization by water-stable soil aggregates, which are formed at sequential WDCs. Cu NPs are dissolved by soil solution, so their mobility (in ionic forms) increases after each subsequent WDCs. The relative content of Cu2+ sourced from Cu NPs increases up to 0.88% after four WDCs. It has been found that mineral NPs of soil can play an important role in the transport of insoluble engineered NPs. As for soluble NPs, the kinetics of their dissolution governs their mobility in ionic forms.

International audience; Nanoparticles (NPs) in the environment have a potential risk for human health and the ecosystem due to their ubiquity, specific characteristics, and properties (extreme mobility in the environment, abilities to accumulate of toxic elements and penetrate into living organisms). There is still a gap in studies on the chemical composition of natural NPs. The main reason is the difficulty to recover NPs, which may represent only one-thousandth or less of the bulk environmental sample, for further dimensional and quantitative characterization. In the present study, a methodology for the recovery of the nanoparticle fraction from polydisperse environmental samples was developed taking as example volcanic ashes from different regions of the world. For the first time, three separation methods, namely, filtration through a 0.45-μm membrane, sedimentation, and coiled tube field-flow fractionation (CTFFF), were comparatively studied. The separated fractions were characterized by laser diffraction and scanning electron microscopy and then analyzed by inductively coupled plasma atomic emission and mass spectrometry. It has been shown that all three methods provide the separation of NPs less than 400 nm from the bulk material. However, the fraction separated by sedimentation also contained a population (5% in mass) of submicron particles (~ 400–900 nm). The filtration resulted in low recovery of NPs. The determination of most trace elements was then impossible; the concentration of elements was under the limit of detection of the analytical instrument. The sedimentation and CTFFF made it possible to determine quantifiable concentrations for both major and trace elements in separated fractions. However, the sedimentation took 48 h while CTFFF enabled the fractionation time to be decreased down to 2 h. Hence, CTFFF looked to be the most promising method for the separation of NPs followed by their quantitative elemental analysis.

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.

The investigation of environmental nano- and submicron particles is needed for the assessment of their impact on the environment and human health as well as for understanding various natural and anthropogenic processes. Nano- and submicron particles have an increased mobility, may serve as a “carrier” for toxic and nutrient substances, and hence are of particular interest. So far, there is a lack of knowledge about source, behavior, fate, and toxicity of environmental nano- and submicron particles. This article is focused on the separation and characterization methods, which are currently used for their investigation. The application of sedimentation, centrifugation, membrane filtration, and field- and flow-based techniques to the separation of nano- and submicron particles are discussed. The advantages and limitations of the techniques are briefly summarized. Among characterization/analysis methods, a special attention is given to electron microscopy, light scattering as well as atomic absorption spectroscopy, optical emission, and mass spectrometry.

Road-deposited sediments (RDS) present a sink for traffic-related pollutants including heavy metals (HMs). HMs associated with RDS particles enter the urban aquatic environment during rainfall events and have adverse effects for biota. RDS nanoscale particles (NSPs) require special consideration due to their specific properties, extremely high mobility in the environment, and ability to penetrate into living organisms. In the present work, the contribution of NSPs of RDS to the pollution of urban runoff by HMs has been evaluated for the first time. It has been shown that bulk RDS samples are polluted by HMs as compared to background urban soils (geo-accumulation indexes of Cu and Zn may attain 2-3). Meanwhile, NSPs of RDS are enriched by HMs as compared to bulk samples; concentration factor for Ni, Cu, Zn, Cd, Sn, and Pb in NSPs being varied from 2 to 10. The water-soluble fractions of RDS samples were also analyzed. Results have shown that the content of water-soluble HMs in RDS is insignificant and rarely exceeds 0.5% of the total contents of HMs in the bulk samples; the highest contents are identified for Cu and Pb. It should be noted that the water-soluble fraction is nearly free from Zn and this element is almost entirely present as particulate matter (NSPs). In general, the overall contribution of NSPs and water-soluble fraction of HMs to the pollution of urban runoff is comparable.

It is demonstrated that field-flow fractionation using a rotating coiled column (RCC) can be used for the separation and purification of the polydisperse sorbents based on polystyrene–divinylbenzene. The behavior of the sorbent at different operating parameters of RCC was studied. The mobile phase composition, column rotation speed, and the initial flow rate of the mobile phase were selected, optimized for the isolation of a monodisperse fraction with the particle size 4.5 µm and the separation of particles 0.5–2 µm in size, particle fragments, and residues of sorbent synthesis. It is shown that a 15-mL analytical RCC ensures the efficient fractionation of 100 mg of the sorbent in one experiment taking less than one hour with the yield of the desired fraction greater than 95%. The perspectives for scaling up the fractionation in RCC are evaluated; the possibility of using the method for the preparative separation of particles of different nature is discussed.

Field-flow fractionation (FFF) is a very powerful and versatile set of liquid chromatography-like elution methods. However, conventional FFF separations occur in thin channels and the sample weight injected is usually less than 1 mg to avoid overloading. The fractionation in a rotating coiled column (RCC), which can be attributed to sedimentation FFF, enables the handling sample weight to be increased at least up to 1 g. An uneven distribution of particles in RCC was first observed by Y. Ito et al. in 1966. The work in this direction was continued by P.S. Fedotov et al. in 2000. Regularities of the behaviour of nano- and microparticles of different size and origin in RCCs with different design parameters were systematically studied taking as example silica particles, latex beads, quartz sand, clay minerals, and other samples. The basic principles of the new FFF method were established. The developed method was applied to the speciation analysis of polydisperse environmental samples, in particular, for the separation of soils into silt, clay and sand fractions. For the first time, nano- and submicron particles of street dust have been separated, weighted, characterized by electronic microscopy, and quantitatively analyzed by ICP-MS (after digestion). The elements that may be of anthropogenic origin (Zn, Cr, Ni, Cu, Cd, Sn, Pb) were found to concentrate mainly in0.3 and 0.3-1 μm fractions. It has been shown that the concentrations of Cr, Ni, Zn in the finest fraction (0.3 μm) of street dust can be one order of magnitude higher than the concentrations of elements in bulk sample. The fractionation in RCC was also used for the recovery of a nearly monodisperse fraction (4.5 μm) of a chromatographic sorbent based on polystyrene-divinylbenzene; impurities remaining from the synthesis and smaller particles (1-2 μm) being removed. Study on the fractionation of synthetic samples has demonstrated the applicability of the method to the preparative separation and purification of polydisperse materials.

A method for the continuous-flow fractionation of particles in a transverse centrifugal field in a rotating conoidal coiled (RCC) column has been developed. A model of a planetary centrifuge with a conoidal drum of a special construction has been tested. The effects of the rotation and revolution speed of the conoidal RCC, as well as the direction and pumping rate of the mobile phase on the behavior of particles smaller than 1 μm have been studied. The conditions have been selected and optimized for the retention and elution of spherical particles of the ‘150 nm’, ‘400 nm’, and ‘900 nm’ standard samples of silica gel (Polyscience Inc.). The possibility of using RCC for the analysis and production of monodisperse standard particle samples has been demonstrated. In particular, the ‘900 nm’ particles have been separated from admixtures of small (100–200 nm) particles and nonspherical 1–2 μm particles present in the sample. The separated fractions have been characterized by electron microscopy.

Continuous-flow (dynamic) leaching in a rotating coiled column has been applied to studies on the mobility of Zn, Cd, Cu, Pb, Ni, Sb, As, S, and other potentially toxic elements in atmospherically deposited dust samples collected near a large copper smelter (Chelyabinsk region, Russia). Water and simulated "acid rain" (pH 4) were used as eluents. The technique enables not only the fast and efficient leaching of elements but as well time-resolved studies on the mobilization of heavy metals, sulphur, and arsenic in environmentally relevant forms to be made. It is shown that up to 1.5, 4.1, 1.9, 11.1, and 46.1% of Pb, As, Cu, Zn, and S, correspondingly, can be easily mobilized by water. Taking into consideration that the total concentrations of these elements in the samples under investigation are surprisingly high and vary in the range from 2.7 g/kg (for arsenic) to 15.5 g/kg (for sulphur), the environmental impact of the dust may be dramatic. The simulated acid rain results in somewhat higher recoveries of elements, except Cu and Pb. The proposed approach and the data obtained can very useful for the risk assessment related to the mobility of potentially toxic elements and their inclusion in the biogeochemical cycle.

A new comprehensive approach based on the field-flow fractionation of particles in a rotating coiled column and their characterization by capillary zone electrophoresis and scanning electron microscopy has been applied to the investigation of irregularly shaped hydroxyapatite sibmicron clusters in an aqueous suspension.

For the first time, nano- and submicron particles of street dust have been separated, weighted, and analyzed. A novel technique, sedimentation field-flow fractionation in a rotating coiled column, was applied to the fractionation of dust samples with water being used as a carrier fluid. The size and morphology of particles in the separated fractions were characterized by electronic microscopy before digestion and the determination of the concentration of elements by ICP-AES and ICP-MS. The elements that may be of anthropogenic origin (Zn, Cr, Ni, Cu, Cd, Sn, Pb) were found to concentrate mainly in