Analysis of nanomaterials based on indium and zinc oxides by high resolution continuum source atomic absorption spectrometry
The properties of nanostructured materials based on zinc and indium oxides can be modified by adding alloying elements to obtain the necessary electrical or optical properties. For example, the specificity of the chemical properties of ZnO and In<sub>2</sub>O<sub>3</sub> for the determination of toxic gases is achieved by immobilizing Au, Ag, etc. nanoparticles on their surface. Control of the material composition plays an important role in determining the dependence between the dopant content and functional properties of the materials. The study is aimed at the development of a methodical approach to the multi-element determination of catalytic dopants (Ag, Au) and matrix elements in nanostructured tin and indium oxides atomic using continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS). The matrix of the synthesized nanostructured materials (NM) is formed by the corresponding oxide with possible oxygen deficiency occurred due to the temperature conditions of synthesis (300 - 700°C), and the content of additives (Ag, Au) being varied from 1 to 3 % wt. Pyrolysis and atomization conditions for sequential multi-element atomic absorption analysis are determined. The most suitable pyrolysis temperatures upon HR CS GFAAS determinations of Ag and Au (for both In and Zn oxides), are 1000, 1600, 1200 and 900°C, respectively. The most suitable atomization temperatures for ETAA-NIS determinations of Ag, Au (for indium oxide based NM, Au (for zinc oxide based NM), In, and Zn are 1800, 2200, 2100, 2200, and 1500°C, respectively. The accuracy of analyte determination reached 1 - 4 % rel. The correctness of the results was proved by inductively coupled plasma mass spectrometry. The developed method provides control of the composition of synthesized nanostructured materials for their more efficient use in photovoltaics, as well as in production of chemical sensors for detection of harmful compounds like CO, NO<sub>2</sub>, NH<sub>3</sub>.