Место издания:Ioannes Marcus Marci Spectroscopic Society Brno
Первая страница:162
Последняя страница:162
Аннотация:The object of this study is zooplankton, and more specifically, several taxa of crustaceans,some of which show an unusual enrichment of trace elements (mainly Li) in their tissues. Arapid and sensitive method for elemental analysis of zooplankton is required, which wouldbe easy for on-site implementation (i.e., on board during cruises). The LIBS is well suited forthis purpose. Due to a lack of certified reference materials, it seems reasonable to usecalibration-free (CF) LIBS in this case. We also present a comparison of the CF-LIBS resultswith those obtained by a conventional (calibration-based) technique. Pelletized samples ofzooplankton were ablated by the 4th harmonic of Q-switched Nd:YAG laser (266 nm).Emission spectra were recorded using a Czerny-Turner spectrograph (resolution of 0.05 nmat 589 nm) with a gated ICCD camera within the range of 201—681 nm. Line selection forreliable plasma diagnostics as well as for analytical measurements was guided by modelingwhich involved solving radiative transfer equations under the assumption of LTE. In general,the obtained element ratios in CF-measurements are consistent with ICP-MS and ICP-AESdata. Due to the nature of the samples, analysis involved mainly alkaline and alkaline earthelements (Li, Na, Mg, Si, P, K, Ca, Sr). As for the calibration-based approach, itsstraightforward use was hampered by differences in colours and reflection coefficients ofsamples, so that we had to use normalization to obtain valid calibration curves. Differencesin sample densities also made contributions to signal uncertainties.