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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.

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.

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).

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.

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.