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).

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.