(LIBS) A PROMISING TECHNIQUE, ITS LIMITATIONS AND A PROPOSED METHOD

2012 ◽  
Vol 57 (1) ◽  
Author(s):  
ZUHAIB HAIDER ◽  
YUSOF MUNAJAT ◽  
RAJA KAMARULZAMAN
Keyword(s):  
Plasma Plume ◽  
Limit Of Detection ◽  
Analytical Techniques ◽  
Single Pulse ◽  
Laser Pulses ◽  
Laser Target ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown ◽  
Analytical Accuracy ◽  
Quantitative Analyses

Laser Induced Breakdown spectroscopy (LIBS) is an extremely potential spectroscopic analytical tool. A highly focused laser bean stiochiometerically ablates the surface of the material in the form of a plasma plume. Excited species in the plasma plume emit their characteristic wavelengths upon de-excitation which are collected, dispersed and analyzed for qualitative and quantitative analyses. Basic LIBS setup includes a laser, target sample, optical fiber and a spectrometer. However it has been used in different configurations like single–pulse and double pulse configurations. LIBS has several advantages over other currently practiced analytical techniques in terms of higher resolution, better limit of detection (LOD), negligible sample preparation etc. Despite of all these advantages it is suffering from poor accuracy and reproducibility of results due to uncontrolled atmosphere around the targeted sample and variations in other experimental parameters. In order to improve reliability of LIBS in terms of accuracy and reproducibility we have designed a methodology for experimentation under controlled environmental conditions inside an especially designed ablation chamber. We will make use of multiple simultaneous laser pulses, which are supposed to play a significant role in improving the analytical accuracy of LIBS particularly for non homogeneous samples. In this article we will briefly review the basics of LIBS, its types, common instrumentations, advantages, limitations applications and at the end our proposed methodology.

scholarly journals Laser ablation initiated fast discharge for spectrochemical applications

2014 ◽  
Vol 68 (3) ◽  
pp. 381-388 ◽  
Author(s):  
Milica Vinic ◽  
Milivoje Ivkovic
Keyword(s):  
Laser Ablation ◽  
Plasma Plume ◽  
Analytical Techniques ◽  
Optical Emission ◽  
Single Pulse ◽  
Breakdown Spectroscopy ◽  
Line Intensities ◽  
Emission Enhancement ◽  
Fast Discharge ◽  
Laser Induced Breakdown

The results of an experimental study of the optical emission enhancement possibilities during the single pulse laser induced breakdown spectroscopy of the aluminum alloy are presented. This study is performed in air, argon and helium at different pressures with and without the additional fast electric discharge. The discharge was initiated by plasma plume created by laser ablation of target. The influences of various capacitors and discharge voltages on enhancement of the studied spectral line intensities were also studied. The application of the fast discharge through optical emission enhancement enables lowering of detection limits thus making this spectrochemical method comparable with the other analytical techniques.

scholarly journals Comparison of Elemental Analysis Techniques for the Characterization of Commercial Alloys

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 736
Author(s):  
Peter Seidel ◽  
Doreen Ebert ◽  
Robert Schinke ◽  
Robert Möckel ◽  
Simone Raatz ◽  
...  
Keyword(s):  
Accurate Determination ◽  
Analytical Techniques ◽  
Optical Emission ◽  
Breakdown Spectroscopy ◽  
General Evaluation ◽  
Sample Composition ◽  
Laser Induced Breakdown ◽  
Copper Aluminum

Better quality control for alloy manufacturing and sorting of post-consumer scraps relies heavily on the accurate determination of their chemical composition. In recent decades, analytical techniques, such as X-ray fluorescence spectroscopy (XRF), laser-induced breakdown spectroscopy (LIBS), and spark optical emission spectroscopy (spark-OES), found widespread use in the metal industry, though only a few studies were published about the comparison of these techniques for commercially available alloys. Hence, we conducted a study on the evaluation of four analytical techniques (energy-dispersive XRF, wavelength-dispersive XRF, LIBS, and spark-OES) for the determination of metal sample composition. It focuses on the quantitative analysis of nine commercial alloys, representing the three most important alloy classes: copper, aluminum, and steel. First, spark-OES is proven to serve as a validation technique in the use of certified alloy reference samples. Following an examination of the lateral homogeneity by XRF, the results of the techniques are compared, and reasons for deviations are discussed. Finally, a more general evaluation of each technique with its capabilities and limitations is given, taking operation-relevant parameters, such as measurement speed and calibration effort, into account. This study shall serve as a guide for the routine use of these methods in metal producing and recycling industries.

scholarly journals Rapid Determination of Cadmium Contamination in Lettuce Using Laser-Induced Breakdown Spectroscopy

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2930 ◽  
Author(s):  
Tingting Shen ◽  
Wenwen Kong ◽  
Fei Liu ◽  
Zhenghui Chen ◽  
Jingdong Yao ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Rapid Determination ◽  
Univariate Analysis ◽  
Laser Induced Breakdown Spectroscopy ◽  
Growth Environment ◽  
Breakdown Spectroscopy ◽  
Contamination Degree ◽  
Cd Contamination ◽  
Laser Induced Breakdown

Quick access to cadmium (Cd) contamination in lettuce is important to supervise the leafy vegetable growth environment and market. This study aims to apply laser-induced breakdown spectroscopy (LIBS) technology for fast determination of Cd content and diagnosis of the Cd contamination degree in lettuce. Emission lines Cd II 214.44 nm, Cd II 226.50 nm, and Cd I 228.80 nm were selected to establish the univariate analysis model. Multivariate analysis including partial least squares (PLS) regression, was used to establish Cd content calibration models, and PLS model based on 22 variables selected by genetic algorithm (GA) obtained the best performance with correlation coefficient in the prediction set Rp2 = 0.9716, limit of detection (LOD) = 1.7 mg/kg. K-Nearest Neighbors (KNN) and random forest (RF) were used to analyze Cd contamination degree, and RF model obtained the correct classification rate of 100% in prediction set. The preliminary results indicate LIBS coupled with chemometrics could be used as a fast, efficient and low-cost method to assess Cd contamination in the vegetable industry.

scholarly journals Quantitative Analysis of Cerium-Gallium Alloys Using a Hand-Held Laser Induced Breakdown Spectroscopy Device

Atoms ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 84 ◽  
Author(s):  
Ashwin P. Rao ◽  
Matthew T. Cook ◽  
Howard L. Hall ◽  
Michael B. Shattan
Keyword(s):  
Emission Line ◽  
Limit Of Detection ◽  
Weight Percent ◽  
Emission Lines ◽  
Resolving Power ◽  
Laser Induced Breakdown Spectroscopy ◽  
Significant Heterogeneity ◽  
Emission Data ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown

A hand-held laser-induced breakdown spectroscopy device was used to acquire spectral emission data from laser-induced plasmas created on the surface of cerium-gallium alloy samples with Ga concentrations ranging from 0–3 weight percent. Ionic and neutral emission lines of the two constituent elements were then extracted and used to generate calibration curves relating the emission line intensity ratios to the gallium concentration of the alloy. The Ga I 287.4-nm emission line was determined to be superior for the purposes of Ga detection and concentration determination. A limit of detection below 0.25% was achieved using a multivariate regression model of the Ga I 287.4-nm line ratio versus two separate Ce II emission lines. This LOD is considered a conservative estimation of the technique’s capability given the type of the calibration samples available and the low power (5 mJ per 1-ns pulse) and resolving power ( λ / Δ λ = 4000) of this hand-held device. Nonetheless, the utility of the technique is demonstrated via a detailed mapping analysis of the surface Ga distribution of a Ce-Ga sample, which reveals significant heterogeneity resulting from the sample production process.

scholarly journals Laser-Induced Breakdown Spectroscopy and Principal Component Analysis for the Classification of Spectra from Gold-Bearing Ores

2019 ◽  
Vol 74 (1) ◽  
pp. 42-54 ◽  
Author(s):  
Daniel Diaz ◽  
Alejandro Molina ◽  
David W. Hahn
Keyword(s):  
Principal Component Analysis ◽  
Limit Of Detection ◽  
Principal Component ◽  
Component Analysis ◽  
Emission Lines ◽  
Laser Induced Breakdown Spectroscopy ◽  
Single Shot ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown

Laser-induced breakdown spectroscopy (LIBS) and principal component analysis (PCA) were applied to the classification of LIBS spectra from gold ores prepared as pressed pellets from pulverized bulk samples. For each sample, 5000 single-shot LIBS spectra were obtained. Although the gold concentrations in the samples were as high as 7.7 µg/g, Au emission lines were not observed in most single-shot LIBS spectra, rendering the application of the usual ensemble-averaging approach for spectral processing to be infeasible. Instead, a PCA approach was utilized to analyze the collection of single-shot LIBS spectra. Two spectral ranges of 21 nm and 0.15 nm wide were considered, and LIBS variables (i.e., wavelengths) reduced to no more than three principal components. Single-shot spectra containing Au emission lines (positive spectra) were discriminated by PCA from those without the spectral feature (negative spectra) in a spectral range of less than 1 nm wide around the Au(I) 267.59 nm emission line. Assuming a discrete gold distribution at very low concentration, LIBS sampling of gold particles seemed unlikely; therefore, positive spectra were considered as data outliers. Detection of data outliers was possible using two PCA statistical parameters, i.e., sample residual and Mahalanobis distance. Results from such a classification were compared with a standard database created with positive spectra identified with a filtering algorithm that rejected spectra with an Au intensity below the smallest detectable analytical LIBS signal (i.e., below the LIBS limit of detection). The PCA approach successfully identified 100% of the data outliers when compared with the standard database. False identifications in the multivariate approach were attributed to variations in shot-to-shot intensity and the presence of interfering emission lines.

Analysis of Contamination Soil with Cu from Road Side by Using Laser Ablation Technique

2013 ◽  
Vol 845 ◽  
pp. 441-445 ◽  
Author(s):  
Mustafa Arab ◽  
Noriah Bidin
Keyword(s):  
Soil Sample ◽  
Environmental Protection Agency ◽  
Limit Of Detection ◽  
Fluorescence Emission ◽  
The United States ◽  
Laser Source ◽  
Integration Time ◽  
Experimental Conditions ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown

In this project, laser induced breakdown spectroscopy (LIBS) has been utilized to determine the heavy element (Copper) in soil sample. LIBS was used in this work to measure the detection limit of Cu in soil sample, on the basis of spectral features, many parameters to improve the sensitivity of LIBS detection of copper are proposed. Q-switch Nd:YAG laser pulse was carried out at 90 mJ and wavelength of 1064 nm to excite the soil samples in purpose of produce a fluorescence emission (plasma), which were analyzed via spectrum analyzer. The important experimental conditions such as the energy of laser source, integration time, the distance and angle of optical fiber from the sparks were optimized for obtain a best LIBS signal. Calibration curve of the Cu peak found to be 236.81 nm as the best peak to calculate the limit of detection (LOD) and found in this study about 2 ppm. From the results the concentrations of Cu is realized to be lower than the allowance limits of 1500 ppm according to the United States Environmental Protection Agency USEPA.

Analysis of Enhanced Laser-Induced Breakdown Spectroscopy with Double Femtosecond Laser Pulses

2015 ◽  
Vol 17 (2) ◽  
pp. 147-152 ◽  
Author(s):  
Jie Shen ◽  
Zhengcai Yang ◽  
Xiaoliang Liu ◽  
Yanchao Shi ◽  
Peixi Zhao ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Laser Induced Breakdown Spectroscopy ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown
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