Laser Induced Breakdown Spectroscopy (LIBS); Intermetallic nanoalloys; Nanocomposites Calibration-free; Quantitative analysis;OXYGEN REDUCTION REACTION; PLASMA-MASS SPECTROMETRY; BIFUNCTIONAL ELECTROCATALYSTS; OXIDE NANOPARTICLES; EVOLUTION REACTIONS; ABLATION SYNTHESIS; CATALYTIC-ACTIVITY; AEROSOL-PARTICLES; ALLOY; COBALT

Intermetallic nanoalloys (NAs) and nanocomposites (NCs) have increasingly gained prominence as efficient catalytic materials in electrochemical energy conversion and storage systems. But their morphology and chemical compositions play critical role in tuning their catalytic activities, and precious metal contents. While advanced microscopy techniques facilitate morphological characterizations, traditional chemical characterizations are either qualitative or extremely involved. In this study, we apply Laser Induced Breakdown Spectroscopy (LIBS) for quantitative compositional analysis of NAs and NCs synthesized with varied elemental ratios by our in-house built pulsed laser ablation technique. Specifically, elemental ratios of binary PtNi, PdCo (NAs) and PtCo (NCs) of different compositions are determined from LIBS measurements employing an internal calibration scheme using the bulk matrix species as internal standards. Morphology and qualitative elemental compositions of the aforesaid NAs and NCs are confirmed from Transmission Electron Microscopy (TEM) images and Energy Dispersive X-ray Spectroscopy (EDX) measurements. LIBS experiments are carried out in ambient conditions with the NA and NC samples drop cast on silicon wafers after centrifugation to increase their concentrations. The technique does not call for cumbersome sample preparations including acid digestions and external calibration standards commonly required in Inductively Coupled Plasma -Optical Emission Spectroscopy (ICP-OES) techniques. Yet the quantitative LIBS results are in good agreement with the results from ICP-OES measurements. Our results indicate the feasibility of using LIBS in future for rapid and in situ quantitative chemical characterizations of wide classes of synthesized NM and NCs.

Laser-induced breakdown spectroscopy; Rare earth elements; Aqueous solution; Surface-enhanced;RARE-EARTH-ELEMENTS; QUANTITATIVE-ANALYSIS; ACCURACY IMPROVEMENT; EMISSION; SAMPLES; LIBS; EXTRACTION; LIQUIDS; WATER

Determination of rare earth elements (REEs) plays an important role in the extraction process. In this work, surface-enhanced laser-induced breakdownspectroscopy (SENLIBS) was introduced to detect REEs (lanthanum, cerium, praseodymium, and neodymium elements) in an aqueous solution. The emission lines of La II 394.91 nm, Ce II 418.66 nm, Pr II 422.29 nm, and Nd II 406.10 nm were selected for quantitative analysis by drying the analytical samples on a Zn metal substrate surface and optimizing the experimental parameters. The results showed that the limits of detection (LoDs) for determining La, Ce, Pr, and Nd elements can reach to 0.85, 4.07, 2.97, and 10.98 mu g mL(-1), respectively, which proved that SENLIBS is a feasible method for determining REEs.

Laser-induced breakdown spectroscopy; Silver nanoparticles; Distribution; Root tissues;ARABIDOPSIS-THALIANA; PLANT-SAMPLES; ACCUMULATION; CADMIUM; MATRIX; SIZE

The manuscript presents a procedure for optimal sample preparation and the mapping of the spatial distribution of metal ions and nanoparticles in plant roots using laser-induced breakdown spectroscopy (LIBS) in a double-pulse configuration (DP LIBS) in orthogonal reheating mode. Two Nd:YAG lasers were used; the first one was an ablation laser (UP-266 MACRO, New Wave, USA) with a wavelength of 266 nm, and the second one (Brilliant, Quantel, France), with a fundamental wavelength of 1064 nm, was used to reheat the microplasma. Seedlings of Vicia faba were cultivated for 7 days in CuSO4 or AgNO3 solutions with a concentration of 10 mu mol 1(-1) or in a solution of silver nanoparticles (AgNPs) with a concentration of 10 mu mol 1(-1) of total Ag, and in distilled water as a control. The total contents of the examined metals in the roots after sample mineralization as well as changes.in the concentrations of the metals in the cultivation solutions were monitored by ICP-OES. Root samples embedded in the TissueTek medium and cut into 40 gm thick cross sections using the Cryo-Cut Microtome proved to be best suited for an accurate LIBS analysis with a 50 gm spatial resolution. 2D raster maps of elemental distribution were created for the emission lines of Cu(I) at 324.754 nm and Ag(I) at 328.068 nm. The limits of detection of DP LIES for the root cross sections were estimated to be 4 pg for Cu, 18 pg for Ag, and 3 pg for AgNPs. The results of Ag spatial distribution mapping indicated that unlike Ag+ ions, AgNPs do not penetrate into the inner tissues of Vicia faba roots but stay in their outermost layers. The content of Ag in roots cultivated in the AgNP solution was one order of magnitude lower compared to roots cultivated in the metal ion solutions. The significantly smaller concentration of Ag in root tissues cultivated in the AgNP solution also supports the conclusion that the absorption and uptake of AgNPs by roots of Vicia faba is very slow. LIBS mapping of root sections represents a fast analytical method with sufficient precision and spatial resolution that can provide very important information for researchers, particularly in the fields of plant science and ecotoxicology.

LIBS; Beef; Offal; Copper; PLSR; Chemometrics;MOTION CONDITIONS; TRACE-ELEMENTS; MEAT; SPECTROMETRY; LIBS; CLASSIFICATION; PREDICTION; SAMPLES

Laser induced breakdown spectroscopy (LIBS) is an emerging technique in the field of food analysis which provides various advantages such as minimal sample preparation, chemical free, rapid detection, provision of spatial information and portability. In this study, LIBS was employed for quantitative analysis of copper content in minced beef samples spiked with beef liver over three independent batches. Copper content was determined with graphite furnace atomic absorption spectroscopy (GFAAS) in order to obtain reference values for modelling. Partial least square regression (PLSR) was performed to build a calibration and validation model. A calibration model with a high R-cv(2) of 0.85 and a RMSECV of 43.5 ppm was obtained, confirming a good fit for the model. The validation model showed a good prediction accuracy with a high R-p(2) of 0.85 and RMSEP of 36.8 ppm. Moreover, on a further study to evaluate the spatial capabilities, LIBS was able to successfully map copper content within a pellet, indicating the suitability of LIBS to provide spatial information and therefore potential use on heterogeneous samples. Overall, it can be concluded that LIBS combined with chemometrics demonstrates potential as a quality monitoring tool for the meat processing industry.