ИСТИНА

Recent years have seen an increasing number of publications related to the use of LIBS for the analysis of biological samples, including elemental imaging applications and qualitative chemometrics-based studies. The present study was aimed at developing methods for the elemental analysis of animal and plant tissues (including sea zooplankton). We used five CRMs (BOk-2, EK-1, LB-1, Tr-1, and IAEA-407) and four zooplankton samples from the Arctic Ocean, all pelletized. Emission spectra were obtained using a laboratory setup based on a Nd:YAG laser (λ = 266 nm), a Czerny-Turner spectrograph and an ICCD detector. The laser beam was directed perpendicularly to the sample surface, while the plasma emission was collected side-on. Examination of the spatiotemporal evolution of plasma revealed that H-alpha emission was significantly displaced in comparison to other signals. Therefore, metal lines were also used for electron number density measurements. Temperature was evaluated from Saha-Boltzmann plots, for which calcium lines have proved to be the best. The elemental analysis was done by using both calibration-based and calibration-free strategies. For some elements (e. g. Ca, K), calibration is hampered by matrix effects, self-absorption and absence of CRMs with suitable analyte concentrations. Therefore, CF-LIBS is of particular interest. It was carried out for both spatially integrated and spatially resolved signals in a fashion similar to that described by J. Aguilera et al.1. Semiquantitative calibration-free determination of elements like Li, Na, Mg, P, Ca and Sr in the samples has proved to be possible. For many analytical lines, the using of spatial profiles of temperature, electron number density, and emission of analytical lines led to improvement in the accuracy of determination. The reported study was funded by RFBR and BRFBR, project numbers 20-53-04036 and Б21РМ-085, respectively. [1] J.A. Aguilera, C. Aragón, G. Cristoforetti, E. Tognoni. Application of calibration-free laser-induced breakdown spectroscopy to radially resolved spectra from a copper-based alloy laser-induced plasma, Spectrochim. Acta Part B (2009) 64:685-689. DOI: 10.1016/j.sab.2009.06.002.