scholarly journals Identification of 20 polymer types by means of laser-induced breakdown spectroscopy (LIBS) and chemometrics

2021 ◽  
Author(s):  
Zuzana Gajarska ◽  
Lukas Brunnbauer ◽  
Hans Lohninger ◽  
Andreas Limbeck
Keyword(s):  
Near Infrared ◽  
Laser Energy ◽  
Real Life ◽  
Discrimination Performance ◽  
Laser Induced Breakdown Spectroscopy ◽  
Forward Selection ◽  
Experimental Conditions ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown ◽  
Cluster Purity

AbstractOver the past few years, laser-induced breakdown spectroscopy (LIBS) has earned a lot of attention in the field of online polymer identification. Unlike the well-established near-infrared spectroscopy (NIR), LIBS analysis is not limited by the sample thickness or color and therefore seems to be a promising candidate for this task. Nevertheless, the similar elemental composition of most polymers results in high similarity of their LIBS spectra, which makes their discrimination challenging. To address this problem, we developed a novel chemometric strategy based on a systematic optimization of two factors influencing the discrimination ability: the set of experimental conditions (laser energy, gate delay, and atmosphere) employed for the LIBS analysis and the set of spectral variables used as a basis for the polymer discrimination. In the process, a novel concept of spectral descriptors was used to extract chemically relevant information from the polymer spectra, cluster purity based on the k-nearest neighbors (k-NN) was established as a suitable tool for monitoring the extent of cluster overlaps and an in-house designed random forest (RDF) experiment combined with a cluster purity–governed forward selection algorithm was employed to identify spectral variables with the greatest relevance for polymer identification. Using this approach, it was possible to discriminate among 20 virgin polymer types, which is the highest number reported in the literature so far. Additionally, using the optimized experimental conditions and data evaluation, robust discrimination performance could be achieved even with polymer samples containing carbon black or other common additives, which hints at an applicability of the developed approach to real-life samples. Graphical abstract

Characterization of Amethysts from Sukamara, Central Kalimantan, Using Laser-Induced Breakdown Spectroscopy (LIBS)

2020 ◽  
Vol 1 (2) ◽  
pp. 5-8
Author(s):  
Komang Gde Suastika, Heri Suyanto, Gunarjo, Sadiana, Darmaji
Keyword(s):  
Emission Intensity ◽  
Laser Energy ◽  
Emission Spectra ◽  
Atomic Emission ◽  
Laser Induced Breakdown Spectroscopy ◽  
Chemical Formula ◽  
Central Kalimantan ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown

Abstract - Laser-Induced Breakdown Spectroscopy (LIBS) is one method of atomic emission spectroscopy using laser ablation as an energy source. This method is used to characterize the type of amethysts that originally come from Sukamara, Central Kalimantan. The result of amethyst characterization can be used as a reference for claiming the natural wealth of the amethyst. The amethyst samples are directly taken from the amethyst mining field in the District Gem Amethyst and consist of four color variations: white, black, yellow, and purple. These samples were analyzed by LIBS, using laser energy of 120 mJ, delay time detection of 2 μs and accumulation of 3, with and without cleaning. The purpose of this study is to determine emission spectra characteristics, contained elements, and physical characteristics of each amethyst sample. The spectra show that the amethyst samples contain some elements such as Al, Ca, K, Fe, Gd, Ba, Si, Be, H, O, N, Cl and Pu with various emission intensities. The value of emission intensity corresponds to concentration of element in the sample. Hence, the characteristics of the amethysts are based on their concentration value. The element with the highest concentration in all samples is Si, which is related to the chemical formula of SiO2. The element with the lowest concentration in all samples is Ca that is found in black and yellow amethysts. The emission intensity of Fe element can distinguish between white, purple, and yellow amethyst. If Fe emission intensity is very low, it indicates yellow sample. Thus, we may conclude that LIBS is a method that can be used to characterize the amethyst samples.Key words: amethyst, impurity, laser-induced, breakdown spectroscopy, characteristic, gemstones

The high dependence of polarization resolved laser-induced breakdown spectroscopy on experimental conditions

2012 ◽  
Vol 21 (7) ◽  
pp. 074204 ◽  
Author(s):  
Nakimana Agnes ◽  
Zuo-Qiang Hao ◽  
Jia Liu ◽  
Hai-Yan Tao ◽  
Xun Gao ◽  
...  
Keyword(s):  
Laser Induced Breakdown Spectroscopy ◽  
Experimental Conditions ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown

scholarly journals Combining Laser-Induced Breakdown Spectroscopy (LIBS) and Visible Near-Infrared Spectroscopy (Vis-NIRS) for Soil Phosphorus Determination

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5419 ◽  
Author(s):  
Sara Sánchez-Esteva ◽  
Maria Knadel ◽  
Sergey Kucheryavskiy ◽  
Lis W. de Jonge ◽  
Gitte H. Rubæk ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Variable Selection ◽  
Near Infrared ◽  
Soil Phosphorus ◽  
Laser Induced Breakdown Spectroscopy ◽  
Soil P ◽  
Breakdown Spectroscopy ◽  
Extractable P ◽  
Laser Induced Breakdown ◽  
Wet Chemical

Conventional wet chemical methods for the determination of soil phosphorus (P) pools, relevant for environmental and agronomic purposes, are labor-intensive. Therefore, alternative techniques are needed, and a combination of the spectroscopic techniques—in this case, laser-induced breakdown spectroscopy (LIBS)—and visible near-infrared spectroscopy (vis-NIRS) could be relevant. We aimed at exploring LIBS, vis-NIRS and their combination for soil P estimation. We analyzed 147 Danish agricultural soils with LIBS and vis-NIRS. As reference measurements, we analyzed water-extractable P (Pwater), Olsen P (Polsen), oxalate-extractable P (Pox) and total P (TP) by conventional wet chemical protocols, as proxies for respectively leachable, plant-available, adsorbed inorganic P, and TP in soil. Partial least squares regression (PLSR) models combined with interval partial least squares (iPLS) and competitive adaptive reweighted sampling (CARS) variable selection methods were tested, and the relevant wavelengths for soil P determination were identified. LIBS exhibited better results compared to vis-NIRS for all P models, except for Pwater, for which results were comparable. Model performance for both the LIBS and vis-NIRS techniques as well as the combined LIBS-vis-NIR approach was significantly improved when variable selection was applied. CARS performed better than iPLS in almost all cases. Combined LIBS and vis-NIRS models with variable selection showed the best results for all four P pools, except for Pox where the results were comparable to using the LIBS model with CARS. Merging LIBS and vis-NIRS with variable selection showed potential for improving soil P determinations, but larger and independent validation datasets should be tested in future studies.

scholarly journals Laser-Induced Breakdown Spectroscopy of AL-Samples: Application to Chemical Analysis of Metallic Elementsf

1995 ◽  
Vol 16 (2) ◽  
pp. 75-82 ◽  
Author(s):  
B. Bescós ◽  
J. Castaño ◽  
A. González Ureña
Keyword(s):  
Chemical Analysis ◽  
Simultaneous Detection ◽  
Laser Induced Breakdown Spectroscopy ◽  
Minor Components ◽  
Experimental Conditions ◽  
Breakdown Spectroscopy ◽  
Non Invasive ◽  
Multichannel Analysis ◽  
Laser Induced Breakdown ◽  
On Line

This paper reports on the simultaneous detection of Mg, Mn, Fe and Pb in Al samples using laser-induced breakdown spectroscopy and optical multichannel analysis of the photoablated microplasma. Using calibrated samples, well characterized linear working curves were determined for these minor components over the 0.01–1% concentration range. In addition optimum experimental conditions were found that allow the analysis to be carded out in a fast and non-invasive manner. The potential application of the method to on-line industrial analysis is also suggested.

Sample Presentation Considerations in Laser-Induced Breakdown Spectroscopy in Aqueous Solution

2007 ◽  
Vol 61 (9) ◽  
pp. 1021-1024 ◽  
Author(s):  
Xiao Fang ◽  
S. Rafi Ahmad
Keyword(s):  
Elemental Analysis ◽  
Aqueous Media ◽  
Water Jet ◽  
Laser Induced Breakdown Spectroscopy ◽  
Signal To Noise ◽  
Experimental Conditions ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown ◽  
Sample Presentation ◽  
Presentation Methods

Various sample presentation configurations for elemental analysis in aqueous media by laser-induced breakdown spectroscopy (LIBS) have been tested and analyzed. Direct and quantitative comparison between the two different sample presentation methods, plasma excitation within water bulk and on the surface in a water jet, has been carried out using the same LIBS system under the same experimental conditions. Temporal characteristics of light emitted from the plasma induced in both the water bulk and the jet surface containing calcium (Ca) were recorded and presented. Spectral data recorded under optimum detection gating conditions showed that the signal-to-noise ratio (S/N) for excitation in the water jet configuration is approximately 10 times higher than that in the bulk excitation, the actual values of enhancement being dependent on the element type. The typical spectra of aqueous samples containing sodium (Na), calcium (Ca), zinc (Zn), cadmium (Cd), and mercury (Hg) were detected and the signal-to-noise ratios were evaluated and compared for the sample presentation configurations under considerations. The results suggest that for better sensitivity of detection, a simple water jet sample presentation configuration could be designed and implemented for cost-effective commercial use of this technique for elemental analysis in a water environment.

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