Use Of Laser-induced Breakdown Spectroscopy Research Articles

Monitoring of the Femtosecond Laser Micromachining Process of Materials Immersed in Water by Use of Laser-Induced Breakdown Spectroscopy

Monitoring of the Femtosecond Laser Micromachining Process of Materials Immersed in Water by Use of Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy for elemental characterization of calcitic alterations on cave walls.

Cave walls are affected by different kinds of alterations involving preservative issues in the case of ornate caves, in particular regarding the rock art covering the walls. In this context, coralloids correspond to a facies with popcorn-like aspect belonging to the speleothem family, mostly composed of calcium carbonate. The elemental characterization indicates the presence of elements that might be linked to the diagenesis and the expansion of the alterations as demonstrated by prior analyses on stalagmites. In this study, we report the use of laser-induced breakdown spectroscopy (LIBS) to characterize the elemental composition of one coralloid sample with a portable instrument allowing punctual measurements and a laboratory mapping setup delivering elemental images with spatial resolution at the micrometric scale, being particularly attentive to Mg, Sr, and Si identified as elements of interest. The complementarity of both instruments allows the determination of the internal structure of the coralloid. Although a validation based on a reference technique is necessary, LIBS data reveal that the external layer of the coralloid is composed of laminations correlated to variations of the LIBS signal of Si. In addition, an interstitial layer showing high LIBS signals for Fe, Al, and Si is interpreted to be a detrital clay interface between the external and the internal part of the coralloid. These preliminary results sustain a possible formation scenario of the coralloid by migration of the elements from the bedrock.

Quantification of fluorine traces in solid samples using CaF molecular emission bands in atmospheric air Laser-Induced Breakdown Spectroscopy

Direct solid determination of trace amounts of fluorine using Laser-Induced Breakdown Spectroscopy (LIBS) is a challenging task due to the low excitation efficiency of this element. Several strategies have been developed to improve the detection capabilities, including the use of LIBS in a He atmosphere to enhance the signal to background ratios of F atomic emission lines. An alternative method is based on the detection of the molecular compounds that are formed with fluorine in the LIBS plasma. In this work, the detection of CaF molecular emission bands is investigated to improve the analytical capabilities of atmospheric air LIBS for the determination of fluorine traces in solid samples. In particular, Cu matrix samples containing different fluorine concentration (between 50 and 600μg/g), and variable amounts of Ca, are used to demonstrate the linear relationships between CaF emission signal and F concentration. Limits of detection for fluorine are improved by more than 1 order of magnitude using CaF emission bands versus F atomic lines, in atmospheric-air LIBS. Furthermore, a toothpaste powder sample is used to validate this analytical method. Good agreement is observed between the nominal and the predicted fluorine mass-content.

Identification of British one pound counterfeit coins using laser-induced breakdown spectroscopy

The use of laser-induced breakdown spectroscopy (LIBS) as a low-cost, nondestructive method for detecting counterfeit coins was examined. A pulsed laser was used to evaporate a minute amount of coin surface, and the emanating plasma was interrogated with an entry-level spectrometer. The spectra produced showed evidence of lead content in six of the eight counterfeits examined. Thus, LIBS could offer a viable low-cost technique for identifying a significant number of fake coins.

Inclusion Detection in Molten Aluminum: Current Art and New Avenues for In Situ Analysis

In order for light metals to meet the demands for critical applications in the automotive and aerospace industries, tight control over the composition and cleanliness of the metal must be achieved before casting. Melt cleanliness manifests primarily in the amount of inclusions present. A review of the state of the art in detecting and quantifying solid particle inclusions is given. Quick analysis of melt composition and quality, carried out in situ, is of great value in casting operations. Such quick measurements in the liquid alleviate analyzing samples in the solid state and thus increase productivity. The use of laser-induced breakdown spectroscopy as a new tool for quantifying melt cleanliness in situ is discussed.

Detection of rare earth elements in Powder River Basin sub-bituminous coal ash using laser-induced breakdown spectroscopy (LIBS)

We reported our preliminary results on the use of laser-induced breakdown spectroscopy to analyze the rare earth elements contained in ash samples from Powder River Basin sub-bituminous coal (PRB-coal). We have identified many elements in the lanthanide series (cerium, europium, holmium, lanthanum, lutetium, praseodymium, promethium, samarium, terbium, ytterbium) and some elements in the actinide series (actinium, thorium, uranium, plutonium, berkelium, californium) in the ash samples. In addition, various metals were also seen to present in the ash samples.

Laser-induced breakdown spectroscopy to determine soil texture: A fast analytical technique

The analysis of soil texture is crucial for the proper management of agricultural systems and for environmental studies. Soil texture is important as it affects erosion potential, water retention capacity, organic matter complexation, and the retention of nutrients, among others. It is usually determined by pipette or hydrometer methods, but analysis requires a preparation with chemical reagents, which can take hours and hence is unfeasible for large number of samples. Here we propose the use of laser-induced breakdown spectroscopy (LIBS) to estimate the proportions of sand, silt, and clay in 60 Brazilian soil samples of varying composition. Two calibration models were developed with the partial least square regression method: one considering the spectral region from 188 to 980nm and the other, emission lines of the elements Si, Na, Fe, Ti, Ca, K, Al, Co, Mg, V, Ba, and Be. The Pearson correlation coefficients for the estimated values were 0.89 and 0.90 on average for the first and second models, respectively. The uncertainties were 6% on average for both models. These results demonstrate the use of LIBS for rapid scanning of the texture of soil samples with distinct composition. The procedure presented here can be extended to other chemical and physical soil properties, which makes LIBS a universal tool for rapid soil analysis without preparation with chemical reagents.

Laser-induced breakdown spectroscopy (LIBS) of a high-pressure CO2-water mixture: application to carbon sequestration.

Geologic carbon storage in deep saline aquifers is considered a feasible and possible approach of mitigating the problem of increasing greenhouse gas emissions. However, there are latent risks in which carbon dioxide (CO2) could migrate from the deep saline formations to shallower aquifers. In the event of a significant CO2 leakage to an underground source of drinking water, CO2 will dissolve in the water, thereby increasing its acidity, which could potentially enhance the solubility of various aquifer constituents, including hazardous compounds, subsequently compromising groundwater quality due to increased concentration of aqueous metals. In this paper we explore the possibility of detecting such leakage by the use of laser-induced breakdown spectroscopy (LIBS). The experiments were conducted in calcium chloride solution at three pressures of 10, 50, and 120 bar. To evaluate the direct effect of elevated CO2 on the intensity of calcium emission lines (422.67 and 393.37 nm), we also performed experiments with pure nitrogen (N2) gas, offering large water solubility contrast. We found that when performed in presence of CO2, LIBS showed only a modest decrease in Ca emission intensity from 10 to 120 bar compared to N2. These results indicate that LIBS is a viable tool for measuring brine/water contents in high-pressure CO2 environment and can be applied for monitoring CO2 leakage and displaced brine migration.

Application of laser-induced breakdown spectroscopy in carbon sequestration research and development

The success of carbon capture and storage (CCS) programme relies on the long-term isolation of CO2 from the atmosphere. Therefore, technologies concomitant to physical storage of CO2 such as reliable measurement, monitoring, and verification (MMV) techniques are needed to ensure that the integrity of the storage site is maintained. We propose the use of laser-induced breakdown spectroscopy (LIBS) analytical technique to detect carbon dioxide leaks to aid in the successful application of CCS. LIBS has a real-time monitoring capability and can be reliably used for the elemental and isotopic analysis of solid, liquid, and gas samples. The flexibility of probe design and use of fibre optics make it a suitable technique for real time measurements in harsh conditions and at hard-to-reach places. Proposed monitoring with LIBS includes terrestrial soil samples, water samples from monitoring wells or from different formations, air samples from monitoring wells or suspected leakage areas. This work details the laboratory scale experiments to measure carbon contents in rock, soil, aqueous, and air samples. The potential of the technology for measurements in high pressure high-temperature conditions will also be discussed.

Potential of laser-induced breakdown spectroscopy for discrimination of nano-sized carbon materials. Insights on the optical characterization of graphene

Since its invention in 2004, graphene has attracted considerable interest worldwide. Advances in the use of graphene in materials science and engineering require important increases in the quality of the final product for integration in photonic and electronic devices. To meet this demand, which will become increasingly strict in the future, analytical techniques capable of differentiating between the starting materials and graphene need to be developed. The interest in the use of laser-induced breakdown spectroscopy (LIBS) for this application rests on the rapid progress experienced by this technology for identification of carbon-based materials of close chemical composition. The potential of LIBS has been explored here by a careful investigation of the spectral properties of both multi-layer and few-layer graphene, graphite and graphene oxide. Results reveal significant differences in the specific optical emission responses of these materials, expressly reflected on the behavior of CN and C2 molecular emissions. These differences result from the particularities of the materials, such as the number of carbon layers and the carbon hybridization in the bonding structure, together with the post-ablation evolution of the concerned plasma plume. In short, this interconnection between ablation and emission events generated from each material allows its characterization and its differentiation from other materials with highly similar chemical composition.

Herbal medicine as an alternative medicine for treating diabetes: the global burden.

Herbal medicine as an alternative medicine for treating diabetes: the global burden.

Classification of vegetable oils based on their concentration of saturated fatty acids using laser induced breakdown spectroscopy (LIBS)

Spectrochemical analyses of organic liquid media such as vegetable oils and sweetened water were performed with the use of LIBS. The aim of this work is to study, on the basis of spectral analyses by LIBS technique of “Swan band” of C2 emitted by different vegetable oils in liquid phase, the characteristics of each organic media. Furthermore this paper proposes, as a classification, a single parameter that could be used to determine the concentration of saturated fatty acids of vegetable oils. A Nd:YAG operating at λ=532nm and an energies per pulse of 30mJ was focused onto the surface of the liquid in ambient air. Following ablation of vegetable oils and sweetened water, we find that vibrational bonds of C2 were released from the molecule containing carbon–carbon bonds linear. In the case of vegetable oils, we find a clear relationship between C2 emission from the plasma and the concentration of saturated fatty acids in the oil.

The use of laser-induced breakdown spectroscopy for the determination of fluorine concentration in glass ionomer cement

The influence of He atmosphere and gate width in laser-induced breakdown spectroscopy (LIBS) determination of fluorine concentration was investigated in detail. The measurements were realized on two double pulse LIBS devices featuring different parameters. Calibration curves, describing the relationship between the fluorine concentration and the corresponding intensity of the LIBS signal, were constructed for both LIBS devices, with and without He flow, respectively. Detection limits achieved were in the range 1.18-0.47wt.%. The best LOD value was obtained in He atmosphere. The LIBS measurement of fluorine content is influenced by different gate widths and the atmosphere in the working chamber. The proposed method was successfully applied to the determination of fluorine concentration in glass ionomer cements.

Depth-Resolved Multilayer Pigment Identification in Paintings: Combined Use of Laser-Induced Breakdown Spectroscopy (LIBS) and Optical Coherence Tomography (OCT)

A detailed feasibility study on the combined use of laser-induced breakdown spectroscopy with optical coherence tomography (LIBS/OCT), aiming at a realistic depth-resolved elemental analysis of multilayer stratigraphies in paintings, is presented. Merging a high spectral resolution LIBS system with a high spatial resolution spectral OCT instrument significantly enhances the quality and accuracy of stratigraphic analysis. First, OCT mapping is employed prior to LIBS analysis in order to assist the selection of specific areas of interest on the painting surface to be examined in detail. Then, intertwined with LIBS, the OCT instrument is used as a precise profilometer for the online determination of the depth of the ablation crater formed by individual laser pulses during LIBS depth-profile analysis. This approach is novel and enables (i) the precise in-depth scaling of elemental concentration profiles, and (ii) the recognition of layer boundaries by estimating the corresponding differences in material ablation rate. Additionally, the latter is supported, within the transparency of the object, by analysis of the OCT cross-sectional views. The potential of this method is illustrated by presenting results on the detailed analysis of the structure of an historic painting on canvas performed to aid planned restoration of the artwork.

Laser-Induced Breakdown Spectroscopy for Chemical Mapping of Materials

: 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.

Qualitative evaluation of maternal milk and commercial infant formulas via LIBS

This study focuses on the use of laser-induced breakdown spectroscopy (LIBS) for the evaluation of the nutrients in maternal milk and some commercially available infant formulas. The results of such evaluation are vital for adequate and healthy feeding for babies during lactation period. Laser-induced breakdown spectroscopy offers special advantages in comparison to the other conventional analytical techniques. Specifically, LIBS is a straightforward technique that can be used in situ to provide qualitative analytical information in few minutes for the samples under investigation without preparation processes. The samples studied in the current work were maternal milk samples collected during the first 3 months of lactation (not colostrum milk) and samples from six different types of commercially available infant formulas. The samples' elemental composition has been compared with respect to the relative abundance of the elements of nutrition importance, namely Mg, Ca, Na, and Fe using their spectral emission lines in the relevant LIBS spectra. In addition, CN and C2 molecular emission bands in the same spectra have been studied as indicators of proteins content in the samples. The obtained analytical results demonstrate the higher elemental contents of the maternal milk compared with the commercial formulas samples. Similar results have been obtained as for the proteins content. It has been also shown that calcium and proteins have similar relative concentration trends in the studied samples. This work demonstrates the feasibility of adopting LIBS as a fast, safe, less costly technique evaluating qualitatively the nutrients content of both maternal and commercial milk samples.

Characterization of Li deposition on the first wall of EAST using laser-induced breakdown spectroscopy

Our recent investigations have indicated that laser-induced breakdown spectroscopy (LIBS) may have great potential in the monitoring of the deposition features of plasma-facing materials (PFMs) in experimental advanced superconducting tokamak (EAST). Detailed information on these PFM can be obtained in real time by analyzing the spectra from 200 to 980 nm. The depth distribution of the main elements from PFMs of the EAST divertor was here investigated. The decrease in the concentrations of main deposed elements (such as Li, Fe, and Cr) were clearly observable after the first ten laser pulses at a laser power density of 5 × 109 W/cm2. The concentrations of substrate elements were found to be uniformly distributed along the depth axis. The use of LIBS for the characterization of quasi three-dimensional multielement distribution maps of the deposition of impurities in the gaps between divertor tiles is here presented. This significantly improves the understanding of the Li deposition behavior of EAST.

Detection of Pesticides and Dioxins in Tissue Fats and Rendering Oils Using Laser-Induced Breakdown Spectroscopy (LIBS)

In laser-induced breakdown spectroscopy (LIBS), a series of powerful laser pulses are directed at a surface to form microplasmas from which light is collected and spectrally analyzed to identify the surface material. In most cases, no sample preparation is needed, and results can be automated and made available within seconds to minutes. Advances in LIBS spectral data analysis using multivariate regression techniques have led to the ability to detect organic chemicals in complex matrices such as foods. Here, the use of LIBS to differentiate samples contaminated with aldrin, 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin, chlorpyrifos, and dieldrin in the complex matrices of tissue fats and rendering oils is described. The pesticide concentrations in the samples ranged from 0.005 to 0.1 μg/g. All samples were successfully differentiated from each other and from control samples. Sample concentrations could also be differentiated for all of the pesticides and the dioxin included in this study. The results presented here provide first proof-of-principle data for the ability to create LIBS-based instrumentation for the rapid analysis of pesticide and dioxin contamination in tissue fat and rendered oils.

Use of laser-induced breakdown spectroscopy for the detection of glycemic elements in Indian medicinal plants.

The demand for interdisciplinary research is increasing in the new millennium to help us understand complex problems and find solutions by integrating the knowledge from different disciplines. The present review is an excellent example of this and shows how unique combination of physics, chemistry, and biological techniques can be used for the evaluation of Indian medicinal herbs used for treating diabetes mellitus. Laser-induced breakdown spectroscopy (LIBS) is a sensitive optical technique that is widely used for its simplicity and versatility. This review presents the most recent application of LIBS for detection of glycemic elements in medicinal plants. The characteristics of matrices, object analysis, use of laser system, and analytical performances with respect to Indian herbs are discussed.

Trace elemental analysis by laser-induced breakdown spectroscopy—Biological applications

Laser-Induced Breakdown Spectroscopy (LIBS) is a sensitive optical technique capable of fast multi-elemental analysis of solid, gaseous and liquid samples. Since the late 1980s LIBS became visible in the analytical atomic spectroscopy scene; its applications having been developed continuously since then. In this paper, the use of LIBS for trace element determination in different matrices is reviewed. The main emphasis is on spatially resolved analysis of microbiological, plant and animal samples.