Место издания:Ioannes Marcus Marci Spectroscopic Society Brno
Первая страница:160
Последняя страница:161
Аннотация:It has recently been discovered that some zooplankton organisms (viz. several taxa of seacrustaceans) accumulate trace elements like lithium, arsenic and uranium [1]. Causes andmechanisms underlying this phaenomenon are unclear. It is therefore of interest to find outwhich changes of chemical composition of tissues accompany the accumulation of theelements. The goal of this study was to establish correlations between analytical signals ofLi, As, and U, on the one hand, and analytical signals of other elements and moleculescomprising the tissues, on the other hand. To this end, atomic and molecular spectroscopydata were recorded and compared. Atomic spectroscopy was represented by laser-inducedbreakdown spectroscopy (LIBS) and ICP-MS with laser ablation (LA-ICP-MS). LIBS waschosen based on its rapidity and sensitivity towards light elements (like Li), while LA-ICP-MS was needed to ensure sufficient sensitivity towards As and U. The instrumentation usedenabled to obtain emission spectra in a wide wavelength range (186—1049 nm). Molecularcomposition was studied by Raman scattering spectroscopy (excitation at 780 nm). Bulkcomposition data, obtained by ICP-AES and ICP-MS after digestion, were also available.Correlations between intensities of atomic emission lines, mass spectrum peaks, andparameters of Raman bands were calculated. We have also made an attempt of sampleclassification. All this was achieved by well-known chemometric approaches (PLS, PCR, PCA,classification tree, and ordinary LS). The results show that, in general, high level ofaccumulated trace elements positively correlates with a band-rich Raman spectrum withrelatively low fluorescence background. Our collection of samples (ca. 30 pcs.) comprisedseveral crustacean species, and Raman spectral fingerprints of subclass Copepoda weresubstantially different from those of other taxa. Apart from that, uranium content exhibitedweak negative correlations with content of most other elements.