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Author(s): M. S. Ermolin [sup.1] , P. S. Fedotov [sup.1] Author Affiliations: (1) grid.439081.7, 0000 0004 0380 8849, Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, , [...], The study of natural and anthropogenic dust and soil nanoparticles is an urgent task of analytical chemistry and biogeochemistry, the solution of which requires the use of complementary separation and analysis methods. In this work, the existing approaches to the isolation of nanoparticles from natural polydisperse samples are summarized. Methods of extracting nanoparticles with aqueous solutions, a possibility of intensifying the process of extracting nanoparticles by an ultrasonic field, methods of cloud-point extraction, and also methods for purifying the separated fractions of nanoparticles from impurities of microparticles are considered. The advantages and disadvantages of these methods are evaluated. It is noted that the success of a study of soil and dust nanoparticles depends on the competent choice of a set of methods for isolating nanoparticles from polydisperse samples and their purification from microparticle impurities, as well as methods for the characterization and elemental analysis of nanoparticles. Particular attention is paid to single particle inductively coupled plasma mass spectrometry as a promising method for determining the concentration, size distribution, and elemental composition of nanoparticles.

Author(s): V. P. Kolotov [sup.1] , D. N. Dogadkin [sup.1] , V. E. Zaichik [sup.2] , V. I. Shirokova [sup.1] , N. N. Dogadkin [sup.1] Author Affiliations: (1) grid.439081.7, 0000 [...], To expand the available tools for the analysis of samples of biological and plant origin of small mass (10-20 mg) using ICP MS, we developed a construction made of three compact teflon reaction minivessels (inserts) of an internal volume of 3 mL, placed in a standard autoclave (EasyPrep) of a volume of 100 cm.sup.3 of a MARS-5 microwave system (CEM). The acid digestion of samples in reaction minivessels requires no more than 1.5 mL of highly pure acids. The digestion of samples proceeds in the common gas atmosphere of a standard autoclave filled with a needed volume of acids of pure for analysis grade. The method was tested on reference materials of plants and biological sample. The results obtained are in agreement with the certified values. The developed method ensures the decrease of the detection limits and obtaining new data on the concentrations of B, Ga, Y, Nb, Tl, Bi, and a number of rare-earth elements in the reference materials.

Author(s): Jiangyi Zhang [sup.1] [sup.2] , Zhifang Xu [sup.1] [sup.2] Author Affiliations: (1) grid.458476.c, 0000 0004 0605 1722, Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, [...], Direct determination of dissolved silicon (DSi) in atmospheric precipitation by ICP-MS is still a challenge because of the presence of serious mass interferences. In this work, a reliable method based on CH.sub.4-Ar mixed gas plasma DRC-ICP-MS was successfully used for the direct determination of DSi in atmospheric precipitation samples. The interfering ions (.sup.14N.sup.14N.sup.+, .sup.12C.sup.16O.sup.+) were directly removed by the reaction with carbon dioxide gas and could be reduced by up to 99% at m/z 28. In addition, the sensitivity of .sup.28Si.sup.+ was 2-fold improved by CH.sub.4 modifier that was introduced to the ICP plasma at 2 mL/min, and the background signal was decreased to 60%. Under the optimized conditions, the limit of quantification was 5 [mu]g/L, and the reproducibility (RSD) was generally less than 3%. The proposed method was assessed using surface water standard reference materials, and the measured values agreed well with the certified values.