Mass Spectrometry

Biography

Biography: Alexander A. Sysoev

Abstract

The report examines the various trends in laser mass spectrometry for elemental analysis. The potential possibilities of laser ablation, laser ionization, ionization of gas-forming impurities are regarded. It analyzes the basic physical processes in during the generation of ions by the laser irradiation and conditions of adequately displaying  the composition of the sample using the laser plasma. The new concept of implementation standardless elemental analysis by using a laser time-of-flight mass spectrometer is offered. The key provisions of the concept are both a complete ionization of the vaporized sample by laser pulse of a local volume and without a discriminatory transmission and detection of the ion packets of any element with the help of the mass analyzer. Discriminatory factors are analyzed at different stages of the ion separation. Different approaches of construction of analytical systems for measuring the ion composition by means of various TOF analyzers. The elemental analysis by laser ionization highlighted three main areas: 1) routine elemental analysis in various industrial technologies for production of solid materials where it is enough to have the resolution R = 500 - 800, the detection limit equals 0.1 - 1 ppm; 2) the elemental analysis of high-purity substances, where it is necessary resolution at the level of R~10⁴, and the detection limit about hundreds of ppt; 3) trace element analysis of gas-forming, where it is necessary to have a detection limit in the concentrations  at levels of ~10^-7 - 10^-8%, and the main problem is the high background of adsorbed gases at surface of samples. New principles of analytical systems of laser TOF mass spectrometers are disclosed. Their basis is the synthesis of the ion source and the TOF analyzer as a single separation unit, the rejection of the additional acceleration of ions in the source, the use of innovative analyzers with wedge-form reflectors of ions. Fundamental importance for standardless analysis is the formation of the analytical signal for each element, as the sum of the signals of singly and doubly charged ions for the total spread of ion by energies. Some technical solutions are also