M.P. Mateo

Spectrochemical study for the in situ detection of oil spill residues using laser-induced breakdown spectroscopy.

Laser-induced breakdown spectroscopy (LIBS) has been used to identify the differences or similarities between crude oil and fuel residues. Firstly, a man portable LIBS analyzer was used for the on-site environmental control and analysis of the oil spill from The Prestige. An exhaustive analysis of crude oil and oil spill residues (collected during the field campaign in the Galician Coast) was performed in the laboratory. Characteristics elements in petroleum such as C, H, N, O, Mg, Na, Fe and V were detected. In addition, contributions from Ca, Si and Al in the composition of residues have been found. The use of intensity ratios of line and band emissions in the original fuel (crude oil) and in the aged residues allowed a better characterization of the samples than the simple use of peak intensities. The chemical composition between the crude oil and the fuel residues was found completely different. As well, a statistical method was employed in order to discriminate residues. Although significant differences were observed, no conclusions in terms of age and provenance could be reached due to the unknowledgment in the origin of the samples.

Laser-Induced Breakdown Spectroscopy for Chemical Mapping of Materials

Abstract: Analytical techniques able to perform spatially resolved analysis are highly demanded in the surface analysis and material science fields. Compared to other analytical techniques usually employed, laser-induced breakdown spectroscopy (LIBS) offers several advantages, such as simplicity and robustness of instrumentation, which permit on-line and in situ measurements. No or minimal sample preparation is required, and the analysis of any sample without restrictions on the shape, size, or conductive nature can be performed under atmospheric conditions in a matter of seconds. In this work, a review of the different instrumental approaches employed in the generation of compositional maps as well as a detailed discussion of the different applications that involve the use of LIBS to obtain two-dimensional or even three-dimensional chemical maps is presented.

3D chemical maps of non-flat surfaces by laser-induced breakdown spectroscopy

In this work, the possibility of performing 3D multielemental chemical maps of non-flat samples by laser-induced breakdown spectroscopy (LIBS) is demonstrated for the first time. In a first step, information of surface morphology of the area to be analyzed is obtained and digitized by a simple experimental arrangement. Using this information, a point-to-point map is generated by the LIBS technique preserving, for every position in the analyzed area, a constant distance between sample surface and both focusing and collection systems. Finally, morphological and spectral information are associated by a homemade computer application which allows plotting the compositional maps in different formats. 3D (X, Y and Z-depth) multielemental chemical images of samples presenting different nature and contour will be shown and the feasibility of this approach will be demonstrated.