Roberto-Jesús Lasheras

Strategies for the identification of urinary calculus by laser induced breakdown spectroscopy.

The present work studies two different strategies to identify urinary calculus. On one hand, (linear or parametric and rank or non-parametric) correlation methods using a mu-LIBS system are studied. On the other hand, elemental ratios of reference materials are determined by using a higher-energy laser and an Echelle spectrograph with an ICCD camera, although without microscope. A data-treatment method was applied for each system and real samples of kidney stones--previously analyzed by IR spectroscopy--were used for reliable evaluation of two identification strategies.

Discrimination of organic solid materials by LIBS using methods of correlation and normalized coordinates

The methods of linear and rank correlation and normalized coordinates (MNC) have been applied to the identification of organic solid materials with a very similar chemical composition by laser-induced breakdown spectroscopy (LIBS). The present study evaluated these three statistical methods using an Echelle spectrometer coupled with an intensified charge-coupled device (ICCD). Moreover, three instrumental parameters (laser pulse energy, delay time and integration time) were evaluated in terms of their influence on the signal-to-noise ratio of carbon and hydrogen emission lines. The probability of a right identification can be estimated by means the described methods in this paper. Methods of correlation provide better identification and discrimination than normalized coordinates at a 95% confidence level.

Classifications of Plastic Polymers based on Spectral Data Analysis with leaser induced Breakdown Spectroscopy

In the industry of the plastics recycling, previous separation is very important, since the treatment used for recycling is substantially different according to what polymer it deals with. In this work we propose a quick and effective method for the classification of plastic polymers through laser induced breakdown spectroscopy (LIBS). In order to find which is the best mathematical method to use, five different methods have been proven: Euclidean Distance; Euclidean Distance Squares; Pearsons Correlation Coefficient; Blocks; and four different types of polymers were used as samples: polyethylene; polyethylene-tereftalate; polystyrene; and polypropylene.

Determination of trace metals by voltamperometry in zebra mussel (Dreissena polymorpha) employed as environmental bio-indicator

Abstract In the present work, metals (cadmium, lead, copper, nickel, tin, selenium, and mercury) have been estimated in the Ebro River (Spain) using the zebra mussel (Dreissena polymorpha) as an environmental bio-indicator. In two sequential studies, in 2006 and 2008, concentrations of metals were calculated in water as well as in the shells and fleshes of the zebra mussels. Samples were collected from assorted locations of the river. Metals were determined successfully at trace levels through voltamperometry, a sensitive technique. It has been noted that analysis of bioaccumulators like zebra mussels can be helpful in evaluating metal pollution in water.

Analysis of Pre-Hispanic Archaeological Samples Using Laser-Induced Breakdown Spectroscopy (LIBS)

Abstract Laser-induced breakdown spectroscopy gave excellent results with respect to reproducibility, sensitivity, nondestructiveness, rapid elemental analisys, and depth-profile analisys. In this work, elements contained in pigments from pre-Hispanic ceramics of Cajamarquilla were identified. Also, some textile samples from the Uquira site, located in Asia Valley between Mala and Cañete (Perú), were analyzed. For this purpose, a Quantel Ultra CFR pulsed Nd/YAG laser was used.

Quantitative Analysis of Roman Archeological Ceramics by Laser-Induced Breakdown Spectroscopy

ABSTRACT In recent decades, numerous analytical techniques have been used for the analysis of archeological samples. Laser-induced breakdown spectroscopy (LIBS) is a promising technique due to its practically nondestructive nature and minimal sample preparation. In this work, LIBS was used for the qualitative and quantitative elemental analyses of pottery manufactured in ancient settlements of Rome. The qualitative study showed that the ceramics were composed of Fe, Ca, and Mg. For quantitative analysis, calibration curves of Fe, Ca, and Mg were constructed with reference samples of each element in a KBr matrix with zinc as an internal standard. The results obtained by LIBS were compared with values obtained by atomic absorption.