Determination of Non-Combustible Impurities in Detonation Diamond Nanopowder

To study the physicochemical (including adsorption) properties of nanodiamond, it is necessary to reproducibly obtain a carbon surface of an individual particle without metallic impurities of an unknown composition. Such a surface can be obtained through an additional procedure of the deep purification of a commercially available sample. This work is devoted to a study of the composition of non-combustible impurities of detonation diamond nanopowder. Using inductively coupled plasma mass spectrometry, iron and titanium are identified as the main metallic components of the non-combustible residue, the presence of Cr, Ni, Zr, As, and Sb is qualitatively established. The expected composition of the main molecular ions formed on the surface of the non-combustible residue under laser desorption/ionization mass spectrometry conditions is presented. Based on the results of the mass spectrometric analysis, a version of two-stage chemical treatment of detonation diamond nanopowder is proposed, which made it possible to reduce the mass fraction of non-combustible impurities during annealing in air from 2.0 to 0.1%.