A method for improving the accuracy of calibration-free laser-induced breakdown spectroscopy (CF-LIBS) using determined plasma temperature by genetic algorithm (GA)

Dong, Jinhua; Liang, Long; Wei, Jie; Tang, Hongsheng; Zhang, Tianlong; Yang, Xiao-Feng; Wang, Kang; Li, Hua

doi:10.1039/c4ja00470a

Cited by 42 publications

(18 citation statements)

References 33 publications

(32 reference statements)

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“…It is possible that the self-absorption coefficient may turn out to be greater than one. There are many reasons behind this situation such as selection of the wrong internal reference line or the presence of self-absorption in the reference line [21,22].…”

Section: Quantitative Analysis By the Cf-irsac Methodsmentioning

confidence: 99%

“…The emission spectrum of the laser-produced plasma plume yields important information about the constituent elements and plasma parameters. However, the emission depends on the wavelength of the exciting laser light, the distance of the target sample from the laser, pulse duration, composition of the sample and ambient proposed by Dong et al [21], in which self-absorption effects can be corrected by selecting an internal reference line to correct the intensities of the other spectral lines. A computer programme, a genetic algorithm, has also been used to estimate the plasma temperature.…”

Section: Introductionmentioning

confidence: 99%

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Quantitative analysis of a brass alloy using CF-LIBS and a laser ablation time-of-flight mass spectrometer

Ahmed¹,

Abdullah²,

Ahmed³

et al. 2017

Laser Phys.

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We present a quantitative analysis of a brass alloy using laser induced breakdown spectroscopy, energy dispersive x-ray spectroscopy (EDX) and laser ablation time-of-flight mass spectrometry (LA-TOF-MS). The emission lines of copper (Cu I) and zinc (Zn I), and the constituent elements of the brass alloy were used to calculate the plasma parameters. The plasma temperature was calculated from the Boltzmann plot as (10 000 ± 1000) K and the electron number density was determined as (2.0 ± 0.5) × 10 17 cm −3 from the Stark-broadened Cu I line as well as using the Saha-Boltzmann equation. The elemental composition was deduced using these techniques: the Boltzmann plot method (70% Cu and 30% Zn), internal reference self-absorption correction (63.36% Cu and 36.64% Zn), EDX (61.75% Cu and 38.25% Zn), and LA-TOF (62% Cu and 38% Zn), whereas, the certified composition is (62% Cu and 38% Zn). It was observed that the internal reference self-absorption correction method yields analytical results comparable to that of EDX and LA-TOF-MS.

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Section: Quantitative Analysis By the Cf-irsac Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantitative analysis of a brass alloy using CF-LIBS and a laser ablation time-of-flight mass spectrometer

Ahmed¹,

Abdullah²,

Ahmed³

et al. 2017

Laser Phys.

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show abstract

“…The processing procedure of genetic algorithm is implemented in MATLAB using The Genetic Algorithm Toolbox for MATLAB developed by Sheffield University of England 41 . The balance between exploration and exploitation 42,43 is considered and the parameters of GA are chosen as: (1) Population size: 100 chromosomes; (2) Number of maximum generations: 200 generations (If the optimum chromosomes do not improve in 20 generations or, RMSE of classification is tiny enough, we will terminate the optimizing procedure); (3) Probability of crossover: 0.7, probability of mutation: 0.1, generation gap: 0.9 (probabilities ensure the ergodicity and, generation gap keep the optimal solutions of each generation).…”

Section: Methodsmentioning

confidence: 99%

A method derived from genetic algorithm, principal component analysis and artificial neural networks to enhance classification capability of laser-Induced breakdown spectroscopy

Zhang

Sun

Kong

et al. 2017

AOPC 2017: Optical Spectroscopy and Imaging

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Selection of characteristic lines is a critical work for both qualitative and quantitative analysis of laser-induced breakdown spectroscopy; it usually needs a lot of time and effort. A novel method combining genetic algorithm, principal component analysis and artificial neural networks (GA-PCA-ANN) is proposed to automatically extract the characteristic spectral segments from the original spectra, with ample feature information and less interference. On the basis of this method, three selection manners: selecting the whole spectral range, optimizing a fixed-length segment and optimizing several non-fixed-length sub-segments were analyzed; and their classification results of steel samples were compared. It is proved that selecting a fixed-length segment with an appropriate segment length achieves better results than selecting the whole spectral range; and selecting several non-fixed-length sub-segments obtains the best result with smallest amount of data. The proposed GA-PCA-ANN method can reduce the workload of analysis, the usage of bandwidth and cost of spectrometers. As a result, it can enhance the classification capability of laser-induced breakdown spectroscopy.

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“…Its feasibility was demonstrated by comparing the results obtained with classical LIBS (drawing calibration lines with a series of matrix‐matched certified standards). Dong et al proposed a method for improving the accuracy of CF‐LIBS using the plasma temperature determined by GA. On the basis of the assumption that different samples with a similar matrix ablated in the same conditions have the same plasma temperature, GA was used to simulate the accurate plasma temperature of the unknown samples. The proposed method demonstrated a significant improvement in accuracy compared with the classical CF‐LIBS in the quantitative analysis of aluminum‐bronze alloy samples.…”

Section: Quantitative Analysismentioning

confidence: 99%

Chemometrics in laser‐induced breakdown spectroscopy

Zhang

Tang

2018

Journal of Chemometrics

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Laser-induced breakdown spectroscopy (LIBS) is a new type of elemental analytical technology with the advantages of real-time, online, and noncontact as well as enabling the simultaneous analysis of multiple elements. It has become a frontier analytical technique in spectral analysis. However, the issue of how to improve the accuracy of qualitative and quantitative analyses by extracting useful information from a large amount of complex LIBS data remains the main problem for the LIBS technique. Chemometrics is a chemical subdiscipline of multi-interdisciplinary methods; it offers advantages in data processing, signal analysis, and pattern recognition. It can solve some complicated problems that are difficult for traditional chemical methods. In this paper, we reviewed the research progress of chemometrics methods in LIBS for spectral data preprocessing as well as for qualitative and quantitative analyses in the most recent 5 years (2012-2016). KEYWORDSchemometrics, data preprocessing, laser-induced breakdown spectroscopy, qualitative analysis, quantitative analysis | INTRODUCTIONAs one of the most promising analytical tools in the 21st century, laser-induced breakdown spectroscopy (LIBS) is a novel analytical technique for materials and elements; it is based on atomic emission spectroscopy and a laser as an excitation source. 1-4 In LIBS, a low-energy pulse laser (typically tens to hundreds of millijoules per pulse) generated from a laser device is reflected by a plane mirror and focused by a plano-convex lens onto the sample surface; a laser-induced plasma with high temperature is then generated. The light with different frequencies is radiated during the plasma cooling process, and it is collected by an optical fiber coupled to a spectrometer. The qualitative and quantitative analyses by the LIBS technique can be performed using the wavelength and integrated intensity of the spectral line. A schematic diagram of the LIBS instrument is presented in Figure 1. It consists of Nd:YAG laser, optical part, X-Y-Z manual micrometric stage, optical fiber, spectrometer, Charge coupled device (CCD) camera, and computer.The LIBS technology has benefited from the invention of the ruby crystal laser 5 and was first reported by Brech and Cross. 6 It has become a research focus in the spectral field with the development of laser and optical detection techniques. Compared with conventional analytical tools, LIBS demonstrates some substantial advantages with regards to being rapid, real-time, on-site, and nondestructive while allowing remote detection without complicated sample preparation procedures as well as simultaneous multicomponent analysis. 7-9 Because of these advantages, LIBS technology has been widely used in process analysis and in the control of industrial manufacturing, food supervision, environmental monitoring, historical relic identification, and space exploration. [10][11][12][13] The National Aeronautics and

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A method for improving the accuracy of calibration-free laser-induced breakdown spectroscopy (CF-LIBS) using determined plasma temperature by genetic algorithm (GA)

Abstract: An internal reference-external standard with iteration correction (IRESIC) method is proposed to correct for the self-absorption effect and plasma temperature in CF-LIBS based on an internal reference line and one standard sample.

Cited by 42 publications

References 33 publications

Quantitative analysis of a brass alloy using CF-LIBS and a laser ablation time-of-flight mass spectrometer

Quantitative analysis of a brass alloy using CF-LIBS and a laser ablation time-of-flight mass spectrometer

A method derived from genetic algorithm, principal component analysis and artificial neural networks to enhance classification capability of laser-Induced breakdown spectroscopy

Chemometrics in laser‐induced breakdown spectroscopy

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