RT info:eu-repo/semantics/article
T1 Analytical methodology to elemental quantification of weathered terrestrial analogues to meteorites using a portable Laser-Induced Breakdown Spectroscopy (LIBS) instrument and Partial Least Squares (PLS) as multivariate calibration technique
A1 Gómez Nubla, Leticia
A1 Aramendia, Julene
A1 Fernández Ortiz de Vallejuelo, Silvia
A1 Madariaga Mota, Juan Manuel
AB The present work is focused on the in situ quantitative analysis of Si, Al,Mg, Ca, Ba, Na, and Fe, present in weatheredterrestrial analogues to meteorites (black steel slag and impact glasses), using a portable Laser InducedBreakdown Spectroscopy (LIBS) instrument. For that purpose, several standards pellets of known elemental concentrationswere manufactured. The elemental and molecular homogeneity of the pellets was studied by meansof Scanning Electron Microscopy coupled to Energy Dispersive X-ray spectroscopy (SEM-EDS) and Raman spectroscopy.This checkwas always made before the LIBS analysis. Univariate andmultivariate (Partial Least Squares(PLS) regression) calibration approaches on LIBS spectra were selected as initial calibration models. After a comparisonbetween both approaches, the former was discarded due to the poor linearity of the calibration curves,and PLS regressionwas chosen to treat the LIBS spectra as themultivariate calibration approach (in the ultraviolet(UV) and infrared (IR) spectral ranges). Predictive capabilities of each calibration model were evaluated by calculatingregression coefficient (r), number of PLS factors (rank), relative errors of cross validation (RMSECV), residualpredictive deviation (RPD) and the Bias value. At the end, the simultaneous use of both ranges ofwavelengths was demonstrated to be more fruitful rather than using the individual ones, probably due to thehigher number of emission lines, number of spectral variables and the PLS latent variables for each element.Moreover, a Reference Material was used as external validation, obtaining satisfactory results in the determinationof elements. The predictive ability of the PLSmodelswas evaluated on samples of Darwin Glasses (Australia),Libyan Desert Glasses (Western Desert of Egypt) and black steel slag residues (steelworks of Basque Country).The obtained results were in concordance with the range of composition measured also by X-ray FluorescenceSpectrometer (ED-XRF). Our methodology is a good, rapid, simple and cost-effective alternative for in situ analysisof these terrestrial analogues over other techniques.
PB Elsevier
SN 0026-265X
YR 2018
FD 2018
LK http://uvadoc.uva.es/handle/10324/35258
UL http://uvadoc.uva.es/handle/10324/35258
LA eng
NO Microchemical Journal, 2018, vol. 137. p. 392–401
DS UVaDOC
RD 27-dic-2024