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Line broadening due to plasma processes or the instrument degrade spectral resolution leading to uncertainty in the elemental profile obtained by optical emission spectroscopy. A novel approach to quantify spectral interferences in laser-induced breakdown spectroscopy (LIBS) is introduced. This algorithm establishes a statistical interference factor (SIF) to quantify spectral interferences for individual line assignment in LIBS while using the full information provided by a spectrum. This factor combines fundamentals of plasma emission with a Bayesian analysis of the experimental spectrum using eventual prior knowledge about the sample and/or the conditions of analysis. Two types of prior knowledge were used to interpret spectra from a pure silicon sample as well as a NIST SRM 610 glass sample and alumina with a controlled Ni contamination at different concentrations. Knowledge of the elemental composition confirmed the existence of spectral lines with high sensitivity to interference while other lines are more appropriate for analysis due to their consistent SIFs despite having knowledge of the composition.

Laser-induced breakdown spectroscopy (LIBS) has recently demonstrated its unrivaled performance for broadband elemental imaging of surfaces. The dimensions of the laser sampling spot still being potentially larger than the interfaces of chemical domains, the plasma created at each location can be largely varying and inhomogeneous with contributions from the different sides of the interface. This variation can become problematic when imaging it on fiber bundles connected to multiple spectrometers. A spatially heterogeneous signal would lead to spatially dependent image on the fiber bundle causing inconsistent readings and loss of efficiency. Köhler illumination is used in this study to create a homogenous illumination, regardless of the source homogeneity, thus improving light collection efficiency. The performance of this approach was demonstrated with inhomogeneous spectral sources and applied to the LIBS analysis of a metallic interface, showing up to a sixfold improvement of the homogeneity of the plasma collection.

Forensic palynology has played a crucial role in many criminal investigations, from burglary to homicide, rape, war crimes, terrorism, and drug trafficking. With the emergence of DNA barcoding, pollen genomics has immense potential to classify and identify pollen taxonomically from its genetic signature. In forensic analysis, a non-destructive method for evidence is essential. Thus, several challenges exist for the extraction of DNA from the pollen grains, such as keeping the grain intact for secondary analysis and bypassing the issue of DNA mixtures more likely to be observed in a pollen assemblage. In this study, a new method was developed to address these challenges and was designed to extract genetic material while not destroying the pollen grain on a single grain level. We demonstrate the mehod's efficiency with Pinus echinata, Taxodium distichum, and Plantago lanceolata single pollen grains. Quantitative PCR amplification of two genetic markers, ribulose bisphosphate carboxylase (rbcL) and internal transcribed spacer 2 (ITS2), and digital microscopy demonstrates the non-destructive nature of this novel DNA extraction method from single pollen grains.

Laser ablation has become the most accepted method for direct sampling of solid materials, as in elemental trace analysis by laser-induced breakdown spectroscopy. However, the scarcity of matrix-matched standards or reference materials (such as NIST reference materials for instance) is an obstacle to quantitative analysis, particularly in the area of hard biological materials analysis, such as bones and teeth. If existing, the corresponding certified standards often consist of powders, then compacted as pellets which density, cohesive strength and dopant incorporation are not always representative of the samples under investigation, thereby casting serious uncertainties on calibration protocols. Here, we report on the synthesis of hydroxyapatite reference ceramic materials that can be doped controllably with various elements of interest. The fabrication process involves spiking during synthesis, prior to a hard sintering of pelletized ceramics. As a result, these materials have good chemical homogeneity and ablation properties that mimic those of naturally calcified biological tissues.

Transparent ceramics are important optical materials with applications in street lighting, high-strength windows, electro- and magneto-optical isolators, high-power laser gain media and radiation detectors. Their fabrication most often relies on powder densification techniques carried out at high temperatures, sometimes promoted by sintering additives. Here, we describe the application of laser-induced breakdown spectroscopy (LIBS) for following the concentration levels of silica used as a sintering agent in the fabrication of yttrium aluminum garnet (YAG) transparent ceramics. The sensitivity limit of our protocol reaches a few tens of ppm of silica in YAG ceramic samples, showing that LIBS can be implemented reliably for the rapid assessment of sintering additives in advanced ceramic processing.

International audience; A coupling of thin layer chromatography with laser ablation ICP SF MS was developed for the fractionation of Ni, V, Fe and S in crude oil and its fractions (saturate, aromatic, resin and asphaltene). The detection limits were 18 ng g -1 and 23 ng g -1 for nickel and vanadium, respectively, and a sample could be characterized in terms of the metal distribution as a function of species polarity within 10 min. The method was used to characterize the metal distribution in crude oils of different origins and their different fractions. © 2012 Elsevier B.V. All rights reserved.

International audience; A novel method for the preparation of crude oil samples based on a xerogel matrix was developed for elemental analysis using laser ablation-double focusing sector field inductively coupled plasma-mass spectrometry. The samples and aqueous solution were successfully encapsulated using zirconium n-propoxide. The use of xerogel produces stable and homogeneous pellets, avoids splashing of the sample and allows the use of aqueous inorganic standards to elaborate the calibration curve. Sulfur, nickel and vanadium were selected as test elements and indium was used as the internal standard to correct the variations in the amount of material ablated. The correlation coefficients of the calibration curves for all the elements tested were better than 0.990 except for sulfur. Crude oil results showed no significant statistical differences between the sol-gel results and those obtained with similar studies. © 2012 The Royal Society of Chemistry.