The main advantages of laser sampling are associated with following features: sample preparations as well as consumables are not needed, low risk of sample contamination, good spatial resolution. In mass spectrometry, high laser irradiance can be used for both ablation and ionization processes. The method is especially profitable in time-of-flight mass spectrometry. A new principle of constructing laser ionization time-of-flight mass spectrometer based on wedge-shaped ion mirrors and the absence of electrostatic ion acceleration before mass analysis is discussed. Among advantages of the analyzer there are ability to provide temporal focusing of ions in a wide energy range (±20%), compactness of the analyzer, and minimization of the requirements for power supplies. The approach is expected to be profitable for standardless elemental analysis of solid samples, which should be possible at laser irradiation power density more than 3 × 10W/cm that ensures complete ionization of all elements in a laser plasma. The analytical signal of each element is formed as the sum of the signals for all charge states and the energy scan of the mass spectra is provided.

It is shown that the main reason affecting the accuracy and reproducibility of the elemental analysis of solids with a laser source of ions is the difference in the ionization cross sections of different elements in the generation of laser plasma. Computer modeling was carried out for the evaporation of the sample and generation of laser plasma at different values of laser power density. The aim of modelling was to determine the cause of the low accuracy of analysis by direct selection of ions from the plasma. The researches have shown that we cannot get satisfactory accuracy of analysis using analytical signal formed only on the base of single-charged ions. At the same time, in the formation of an analytical signal, as a sum of the intensities of the mass peaks of all charges of each element, the accuracy of the analysis does not depend either on the ionization cross section or on the nonreproducibility of the laser radiation power. It is shown that this approach completely eliminates the "matrix effect."