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The Mendeleev Periodic Table of Chemical Elements delivered a strong impetus to the development of fundamental and applied chemistry, chemical technology, analytical chemistry, and material sciences. Each element under the Periodic Table is an idealized substance with a certain structure and properties as defined by existing theoretical frameworks. In the real world, we deal with substances that are close in composition to the element of Periodic Table under study but differ in the presence of different elements in them – impurities that distort (sometimes radically) the structure and properties of the target research object. For many centuries, humanity has sought to obtain pure substances in order to achieve desired properties. In the second half of the 20th century, a unique collection of high purity substances was created, which includes samples representing material artifacts, prototypes of elements of Periodic Table that contain record low contents of impurity elements. With ongoing scientific and technological progress, the achieved purity of substances continuously increases and, therefore, their approximation to idealized elements of Periodic Table. This is facilitated by: new technological processes for the production and storage of high purity substances with a constant decrease in the level of impurities; the creation of isotope-friendly substances; complexes of more highly sensitive multi-element analysis methods; identification of the unique properties of high purity substances, bringing them closer to the capabilities of analog elements of Periodic Table and much more. This article is devoted to progress in these areas. Special attention is also paid to the problems in modern analytical chemistry of high purity substances and the use of the latter in the metrology of chemical analysis as the standards of comparison.

A novel approach is developed for the determination of Co and Au dopants in advanced materials based on tin oxide using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS) with direct slurry sampling. Sodium carboxylmethylcellulose (Na-CMC) is an effective stabilizer for diluted suspensions. Use Na-CMC allows to transfer the analytes into graphite furnace completely and reproducibly. The relative standard deviation obtained by HR CS GFAAS was not higher than 4%. Accuracy was proven by means inductively coupled plasma mass spectrometry (ICP-MS) in solutions after decomposition as a comparative technique. To determine Au and Co in the volume of SnO2, the acid decomposition conditions (HCl, HF) of the samples were suggested by means of an autoclave in a microwave oven.

This paper describes the potential of high-resolution continuum source graphite furnace atomic absorption spectrometry for determination of Pt, Pd and Rh after separation and concentration by original in-house developed heterochain polymer S, N-containing sorbent. The methods of sample preparation of spent ceramic-based autocatalysts were considered, two of which were used: autoclave decomposition in mixture of acids HCl:HNO3 (3:1) and high-temperature melting with K2S2O7. Both methods anyway limit the direct determination of analytes by HR CS GFAAS. Using the first method it is an incomplete digestion of spent autocatalysts samples, since the precipitate is Si, and the rhodium metal dissolves with difficulty and partially passes into solution. In contrast to the first method, the second method allow to completely transfer analytes into solution, however, the background signal produced by the chemical composition of the flux, overlaps the analytical zone. It was found, that Pt, Pd and Rh contained in the spent ceramic automotive catalysts could be effectively separated and concentrated by heterochain polymer S, N-containing sorbent, which has high sorption capacity, selectivity and resistant to dilute acids. The chosen HR CS GFAAS analysis conditions enable us to determine Pt, Pd and Rh with good metrological characteristics. The concentrations of Pt, Pd and Rh in two samples of automobile exhaust catalysts were found in range of 0.00015-0.00050; 0.170-0.189; 0.0180-0.0210wt%, respectively. The relative standard deviation obtained by HR CS GFAAS was not more than 5%. Limits of detection by HR CS GFAAS achieved were 6.2·10(-6)wt% for Pt, 1.8·10(-6)wt% for Pd, and 3.4·10(-6)wt% for Rh. Limits of determination achieved by HR CS GFAAS were 1.1·10(-5)wt% for Pt, 6.9·10(-5)wt% for Pd, and 8.3·10(-5)wt% for Rh. To control the accuracy of PGM in sorption concentrates by HR CS GFAAS method, it was appropriate to conduct an inter-method comparative experiment. The researches on the application of atomic-emission spectroscopy method with inductively coupled plasma as a comparative method were conducted. In addition, the trueness control of the obtained results is confirmed by added-found method.

The possibility of group concentration of As, Bi, Sb, Se, and Te using sulfur- and nitrogen-containing sorbents with the subsequent determination by ICP-AES and DCA-AES with MAES in analysis of metal-containing recyclable raw material is studied. Conditions of ICP-AES and DCA-AES with MAES analysis of sorption concentrate from solutions or from solid phase are selected. The developed method makes it possible to determine the listed toxic elements in the range of mass fraction of n × 105−n × 103% (RSD = 15-7 rel %). Accuracy of the results was controlled by varying weighed samples of analytes and by comparison of the results with the known values.

A simple, fast and precise method for the electrothermal atomic absorption spectrometry (ETAAS) determination of Au(III), Ag(I), Pd(II) and Pt(IV) from a single aliquot at the level of 10 −4 % in complex samples was developed. The method is based on reducing the interfering effect of Al, Fe, Cu and Ni macrocomponents on determination of Au(III), Ag(I), Pd(II) and Pt(IV) by ETAAS by adjusting the acidic sample solution to pH 9–11 using aqueous ammonia. As a result, 98.4% of Al and 99.7% of Fe precipitated smoothly at room temperature and without additional reagents needed. Furthermore, Au(III), Ag(I), Pd(II) and Pt(IV) did not co-precipitate and remained in the soluble form as ammonia complexes. While soluble ammonia Ni and Cu complexes were also produced, they decomposed in a graphite furnace at 400 °C and did not interfere with ETAAS determination of noble metals. In addition, the benefit of the ETAAS determination of Au(III), Ag(I) in the ammonia complexes is that there were no losses of Ag and Au due to the formation of insoluble AgCl and vaporization of gold and silver chlorides before atomization or incomplete dissociation in the gas phase when conventional sample treatment methods were used The relative standard deviations (R.S.D.) were in the range of 8–10% for determination of Au and Pd in aluminium catalysts, Ag in pure gold samples, and Pt in nickel tailings.

Regularities of extraction of rhenium (VII) melt tetraoctyl-ammonium bromide in a mixture of higher alcohols and paraffin were determined. Quantitative extraction of measurements obtained in the range of pH of the aqueous phase 1.5–2.0 was carried out. It was shown that the degree of extraction of rhenium is reduced during the transition from sulfuric to nitric acid. The introduction of extracting 20% of higher alcohols improved the solubility of the extracted complex in paraffin. The composition of the complex, calculated, was 3.37±0.4.