Author: Prochazka, D.

Search results

4 articles found

Combination of laser-induced breakdown spectroscopy and Raman spectroscopy for multivariate classification of bacteria

Author: Prochazka, D. ; et. al.

Journal: Spectrochimica Acta Part B: Atomic Spectroscopy (2017)

DOI: 10.1016/j.sab.2017.11.004

Authors
Kaiser, J. ; Klus, J. ; Mazura, M. ; Novotný, J. ; Novotný, K. ; Pořízka, P. ; Prochazková, P. ; Rebrošová, K. ; Samek, O.

Keywords

Laser-induced breakdown spectroscopy; Raman spectroscopy; Chemometrics; Bacteria;

Abstract

In this work, we investigate the impact of data provided by complementary laser-based spectroscopic methods on multivariate classification accuracy. Discrimination and classification of five Staphylococcus bacterial strains and one strain of Escherichia coli is presented. The technique that we used for measurements is a combination of Raman spectroscopy and Laser-Induced Breakdown Spectroscopy (LIBS). Obtained spectroscopic data were then processed using Multivariate Data Analysis algorithms. Principal Components Analysis (PCA) was selected as the most suitable technique for visualization of bacterial strains data. To classify the bacterial strains, we used Neural Networks, namely a supervised version of Kohonen's self-organizing maps (SOM). We were processing results in three different ways - separately from LIBS measurements, from Raman measurements, and we also merged data from both mentioned methods. The three types of results were then compared. By applying the PCA to Raman spectroscopy data, we observed that two bacterial strains were fully distinguished from the rest of the data set. In the case of LIBS data, three bacterial strains were fully discriminated. Using a combination of data from both methods, we achieved the complete discrimination of all bacterial strains. All the data were classified with a high success rate using SOM algorithm. The most accurate classification was obtained using a combination of data from both techniques. The classification accuracy varied, depending on specific samples and techniques. As for LIBS, the classification accuracy ranged from 45% to 100%, as for Raman Spectroscopy from 50% to 100% and in case of merged data, all samples were classified correctly. Based on the results of the experiments presented in this work, we can assume that the combination of Raman spectroscopy and LIBS significantly enhances discrimination and classification accuracy of bacterial species and strains. The reason is the complementarity in obtained chemical information while using these two methods.

Area:

Health ; Instrumentation

Material:

Bacteria

Elements:

Lines [nm]:

N I 742.36 nm N I 744.23 nm N I 746.83 nm

Lines [nm]:

Na I 589.00 nm Na I 589.59 nm

Lines [nm]:

Mg II 279.55 nm Mg II 280.27 nm

Lines [nm]:

K I 766.49 nm K I 769.90 nm

Lines [nm]:

Ca II 393.37 nm Ca II 396.85 nm

...

Emmision lines:
Mg II 279.55 nm
Mg II 280.27 nm
Ca II 393.37 nm
Ca II 396.85 nm
Na I 589.00 nm
Na I 589.59 nm
H I 656.28 nm
N I 742.36 nm
N I 744.23 nm
N I 746.83 nm
K I 766.49 nm
K I 769.90 nm
O I 777.19 nm

Detection of visually unrecognizable braking tracks using Laser-Induced Breakdown Spectroscopy, a feasibility study

Author: Prochazka, D. ; et. al.

Journal: Spectrochimica Acta Part B: Atomic Spectroscopy (2016)

Applications

DOI: 10.1016/j.sab.2016.02.013

Authors
Bilík, M. ; Brada, M. ; Bradáč, A. ; Kaiser, J. ; Klus, J. ; Novotný, J. ; Novotný, K. ; Pořízka, P. ; Prochazková, P. ; Semela, M. ; Ticová, B.

Keywords

Braking tracks; Forensic; LIBS; Tire treads; Laser-Induced Breakdown Spectroscopy;

Abstract

Identification of the position, length and mainly beginning of a braking track has proven to be essential for determination of causes of a road traffic accident. With the introduction of modern safety braking systems and assistance systems such as the Anti-lock Braking System (ABS) or Electronic Stability Control (ESC), the visual identification of braking tracks that has been used up until the present is proving to be rather complicated or even impossible. This paper focuses on identification of braking tracks using a spectrochemical analysis of the road surface. Laser-Induced Breakdown Spectroscopy (LIBS) was selected as a method suitable for fast in-situ element detection. In the course of detailed observations of braking tracks it was determined that they consist of small particles of tire treads that are caught in intrusions in the road surface. As regards detection of the “dust” resulting from wear and tear of tire treads in the environment, organic zinc was selected as the identification element in the past. The content of zinc in tire treads has been seen to differ with regard to various sources and tire types; however, the arithmetic mean and modus of these values are approximately 1% by weight. For in-situ measurements of actual braking tracks a mobile LIBS device equipped with a special module was used. Several measurements were performed for 3 different cars and tire types respectively which slowed down with full braking power. Moreover, the influence of different initial speed, vehicle mass and braking track length on detected signal is discussed here.

Area:

Industry ; LOD ; Traffic

Material:

Braking track

Elements:

Lines [nm]:

Zn I 328.23 nm Zn I 330.26 nm

Emmision lines:
Zn I 328.23 nm
Zn I 330.26 nm

Detection of tire tread particles using laser-induced breakdown spectroscopy

Author: Prochazka, D. ; et. al.

Journal: Spectrochimica Acta Part B: Atomic Spectroscopy (2015)

Applications

DOI: 10.1016/j.sab.2015.03.011

Authors
Bilík, M. ; Bradáč, A. ; Kaiser, J. ; Klus, J. ; Novotný, J. ; Novotný, K. ; Pořízka, P. ; Prochazková, P. ; Semela, M. ; Ticová, B.

Keywords

LIBS; Laser-induced breakdown spectroscopy; Tire tread; Optimization ;

Abstract

The objective of this paper is a study of the potential of laser induced breakdown spectroscopy (LIBS) for detection of tire tread particles. Tire tread particles may represent pollutants; simultaneously, it is potentially possible to exploit detection of tire tread particles for identification of optically imperceptible braking tracks at locations of road accidents. The paper describes the general composition of tire treads and selection of an element suitable for detection using the LIBS method. Subsequently, the applicable spectral line is selected considering interferences with lines of elements that might be present together with the detected particles, and optimization of measurement parameters such as incident laser energy, gate delay and gate width is performed. In order to eliminate the matrix effect, measurements were performed using 4 types of tires manufactured by 3 different producers. An adhesive tape was used as a sample carrier. The most suitable adhesive tape was selected from 5 commonly available tapes, on the basis of their respective LIBS spectra. Calibration standards, i.e. an adhesive tape with different area content of tire tread particles, were prepared for the selected tire. A calibration line was created on the basis of the aforementioned calibration standards. The linear section of this line was used for determination of the detection limit value applicable to the selected tire. Considering the insignificant influence of matrix of various types of tires, it is possible to make a simple recalculation of the detection limit value on the basis of zinc content in a specific tire.

Area:

Industry ; LOD ; Traffic

Material:

Braking track ; Tire

Elements:

Lines [nm]:

Zn I 328.23 nm Zn I 330.26 nm Zn I 334.50 nm

Emmision lines:
Zn I 328.23 nm
Zn I 330.26 nm
Zn I 334.50 nm

RECENT DEVELOPMENT OF DOUBLE PULSE LASER INDUCED BREAKDOWN SPECTROSCOPY (DP LIBS) SETUP

Author: Prochazka, D. ; et. al.

Journal: 10th Workshop of Physical Chemists and Electrochemists, Faculty of Science MU, ed. Libuše Trnková (2010)

Fundamentals

DOI:

Authors
Galiová, M. ; Kaiser, J. ; Malina, R. ; Novotný, K.

Keywords

Abstract

Single pulse (SP) LIBS setup was modified to DP setup to achieve more accurate analytical sensitivity and spatial resolution. All parameters, like interpulse delay, acquisition delay or energy of ablation and excitation laser pulses were optimized.

Area:

Instrumentation

Material:

All materials

Elements:

Emmision lines:

Co-author: Prochazka, D.

Search results

13 articles found

Detection of fluorine using laser-induced breakdown spectroscopy and Raman spectroscopy

Author: Pořízka, P. ; et. al.

Journal: Journal of Analytical Atomic Spectrometry (2017)

Fundamentals Applications

DOI: 10.1039/C7JA00200A

Authors
Čelko, L. ; Gadas, P. ; Häkkänen, H. ; Hrdlička, A. ; Kaiser, J. ; Kaski, S. ; Modlitbová, P. ; Novotný, J. ; Novotný, K. ; Prochazka, D. ; Sládková, L.

Keywords

Abstract

In general, the detection of F and other halogens is challenging through conventional techniques. In this paper, various approaches for the qualitative and quantitative analysis of F using the laser-induced breakdown spectroscopy (LIBS) technique were demonstrated. In LIBS, fluorine detection can be realized by means of atomic lines and molecular bands. For the purposes of our experiment, two sets of pellets with various contents of CaF2, CaCO3 and cellulose were analyzed using a lab-based LIBS system under a He atmosphere. The fluorine atomic line at 685.60 nm was correlated with CaF signals proving their close relationship. Consequently, the limits of detection were determined for both analytical signals. Moreover, conditions necessary for the quantification of F via CaF band signals were estimated. The dependence of the CaF signal on the varying ratio of Ca and F contents was investigated. Finally, a chip of a real CaF2 crystal was prepared and its surface was mapped with Raman and LIBS systems. The obtained elemental and molecular maps showed good numerical correlations. Thus, the yielded results validated the possibility to substitute the fluorine atomic line by non-conventional CaF molecular bands in the qualitative and quantitative LIBS analysis of fluorine.

Area:

Geology ; Mapping

Material:

Fluorite

Elements:

Lines [nm]:

Ca I 422.67 nm Ca I 430.25 nm Ca I 551.30 nm Ca I 585.75 nm Ca II 370.60 nm Ca II 373.69 nm Ca II 393.37 nm Ca II 396.85 nm

Lines [nm]:

F I 685.60 nm

Emmision lines:
Ca II 370.60 nm
Ca II 373.69 nm
Ca II 393.37 nm
Ca II 396.85 nm
Ca I 422.67 nm
Ca I 430.25 nm
Ca I 551.30 nm
Ca I 585.75 nm
F I 685.60 nm

Impact of Laser-Induced Breakdown Spectroscopy data normalization on multivariate classification accuracy

Author: Pořízka, P. ; et. al.

Journal: Journal of Analytical Atomic Spectrometry (2017)

Chemometrics

DOI: 10.1039/C6JA00322B

Authors
Hrdlička, A. ; Kaiser, J. ; Klus, J. ; Novotný, J. ; Novotný, K. ; Prochazka, D. ; Škarková, P. ; Vrábel, J.

Keywords

Abstract

Multivariate data analysis (MVDA) is getting popular across the spectroscopic community. To assess accurate results, the obtained data should be preprocessed prior to utilization of any MVDA algorithm. The process of data normalization or “internal standardization” is widely used across a broad range of applications. In this manuscript we investigate the utilization of Laser-Induced Breakdown Spectroscopy (LIBS) coupled with MVDA. However, many articles regarding the use of MVDA on data from LIBS do not provide any information about the data pretreatment. This work describes the impact of LIBS data normalization approaches on MVDA classification accuracy. Also, the impact of classical data preprocessing (mean centering and scaling) exploiting the prior utilization of MVDA was studied. This issue was investigated exploiting simple soft independent modelling of class analogies algorithm. The findings were generalized for three sample matrices (steel, Al alloys, and sedimentary ores). Furthermore, the selection of an appropriate normalization algorithm is not trivial since the spectrum of each sample matrix is composed of a different number of elements and corresponding elemental lines.

Area:

Geology ; Industry

Material:

Aluminium alloy ; Sedimentary ore ; Steel

Elements:

Lines [nm]:

Fe I 381.58 nm Fe I 382.04 nm Fe I 382.59 nm Fe I 404.58 nm Fe I 438.28 nm Fe I 440.48 nm Fe I 441.51 nm Fe I 487.21 nm Fe I 489.15 nm Fe I 492.05 nm Fe I 495.76 nm Fe I 358.72 nm

Lines [nm]:

Cr II 284.98 nm Cr II 313.21 nm Cr II 336.80 nm Cr I 425.44 nm Cr I 427.48 nm Cr I 428.97 nm Cr I 455.40 nm Cr I 520.84 nm Cr I 540.98 nm

Lines [nm]:

Mg I 285.21 nm Mg I 516.73 nm Mg I 517.27 nm Mg I 518.36 nm Mg II 279.55 nm Mg II 280.27 nm Mg II 293.65 nm

Lines [nm]:

Cu I 324.75 nm Cu I 327.40 nm Cu I 515.32 nm Cu I 521.82 nm

Lines [nm]:

Al I 308.22 nm Al I 309.27 nm Al I 394.40 nm Al I 396.15 nm

...

Emmision lines:
Co II 241.62 nm
Mg II 279.55 nm
Mg II 280.27 nm
Cr II 284.98 nm
Mg I 285.21 nm
Si I 288.16 nm
Mg II 293.65 nm
Al I 308.22 nm
Al I 309.27 nm
Cr II 313.21 nm
Cu I 324.75 nm
Cu I 327.40 nm
Zn I 330.26 nm
Zn I 334.50 nm
Ti II 334.94 nm
Ti II 336.12 nm
Cr II 336.80 nm
Ni I 341.48 nm
Ni I 349.30 nm
Ni I 351.51 nm
Ni I 352.45 nm
Fe I 358.72 nm
Fe I 381.58 nm
Fe I 382.04 nm
Fe I 382.59 nm
Si I 390.55 nm
Al I 394.40 nm
Al I 396.15 nm
Fe I 404.58 nm
Pb I 405.78 nm
Cr I 425.44 nm
Cr I 427.48 nm
Cr I 428.97 nm
Fe I 438.28 nm
Fe I 440.48 nm
Fe I 441.51 nm
Cr I 455.40 nm
Zn I 472.22 nm
Mn I 475.40 nm
Mn I 476.24 nm
Mn I 478.34 nm
Zn I 481.05 nm
Mn I 482.35 nm
Fe I 487.21 nm
Fe I 489.15 nm
Fe I 492.05 nm
Fe I 495.76 nm
Cu I 515.32 nm
Mg I 516.73 nm
Mg I 517.27 nm
Mg I 518.36 nm
Cr I 520.84 nm
Cu I 521.82 nm
Cr I 540.98 nm
Mo I 550.65 nm
Na I 589.00 nm
Na I 589.59 nm
H I 656.28 nm
N I 742.36 nm
N I 744.23 nm
N I 746.83 nm
K I 766.49 nm
K I 769.90 nm
O I 777.19 nm

Application of self-organizing maps to the study of U-Zr-Ti-Nb distribution in sandstone-hosted uranium ores

Author: Klus, J. ; et. al.

Journal: Spectrochimica Acta Part B: Atomic Spectroscopy (2017)

Applications Chemometrics

DOI: 10.1016/j.sab.2017.03.008

Authors
Kaiser, J. ; Mikysek, P. ; Novotný, J. ; Novotný, K. ; Pořízka, P. ; Prochazka, D. ; Slobodník, M.

Keywords

Laser-Induced Breakdown Spectroscopy; Uranium ore; Elements distribution; Self-organizing maps;

Abstract

This paper presents a novel approach for processing the spectral information obtained from high-resolution elemental mapping performed by means of Laser-Induced Breakdown Spectroscopy. The proposed methodology is aimed at the description of possible elemental associations within a heterogeneous sample. High-resolution elemental mapping provides a large number of measurements. Moreover, typical laser-induced plasma spectrum consists of several thousands of spectral variables. Analysis of heterogeneous samples, where valuable information is hidden in a limited fraction of sample mass, requires special treatment. The sample under study is a sandstone-hosted uranium ore that shows irregular distribution of ore elements such as zirconium, titanium, uranium and niobium. Presented processing methodology shows the way to reduce the dimensionality of data and retain the spectral information by utilizing self-organizing maps (SOM). The spectral information from SOM is processed further to detect either simultaneous or isolated presence of elements. Conclusions suggested by SOM are in good agreement with geological studies of mineralization phases performed at the deposit. Even deeper investigation of the SOM results enables discrimination of interesting measurements and reveals new possibilities in the visualization of chemical mapping information. Suggested approach improves the description of elemental associations in mineral phases, which is crucial for the mining industry.

Area:

Geology ; Industry ; Mapping

Material:

Sandstone

Elements:

Lines [nm]:

Si I 251.43 nm Si I 288.16 nm

Lines [nm]:

Ti II 325.42 nm

Lines [nm]:

Fe I 358.12 nm

Lines [nm]:

Zr II 349.62 nm

Lines [nm]:

Nb II 255.14 nm

...

Emmision lines:
Si I 251.43 nm
Nb II 255.14 nm
Si I 288.16 nm
Ti II 325.42 nm
Zr II 349.62 nm
Fe I 358.12 nm
U II 409.01 nm

Improvement of the Laser-Induced Breakdown Spectroscopy method sensitivity by the usage of combination of Ag-nanoparticles and vacuum conditions

Author: Sládková, L. ; et. al.

Journal: Spectrochimica Acta Part B: Atomic Spectroscopy (2017)

Applications

DOI: 10.1016/j.sab.2016.11.005

Authors
Čelko, L. ; Hrdlička, A. ; Kaiser, J. ; Novotný, K. ; Pořízka, P. ; Prochazka, D. ; Remešová, M. ; Škarková, P.

Keywords

Laser-Induced Breakdown Spectroscopy; Silver nanoparticles; Low pressure conditions; Sensitivity improvement;

Abstract

In this work we studied the effect of vacuum (low pressure) conditions on the behavior of laser-induced plasma (LIP) created on a sample surface covered with silver nanoparticles (Ag-NPs), i.e. Nanoparticles-Enhanced Laser-Induced Breakdown Spectroscopy (NELIBS) experiment in a vacuum. The focus was put on the step by step optimization of the measurement parameters, such as energy of the laser pulse, temporally resolved detection, ambient pressure, and different content of Ag-NPs applied on the sample surface. The measurement parameters were optimized in order to achieve the greatest enhancement represented as the signal-to-noise ratio (SNR) of NELIBS signal to the SNR of LIBS signal. The presence of NPs involved in the ablation process enhances LIP intensity; hence the improvement in the analytical sensitivity was yielded. A leaded brass standard was analyzed with the emphasis on the signal enhancement of Pb traces. We gained enhancement by a factor of four. Although the low pressure had no significant influence on the LIP signal enhancement compared to that under ambient conditions, the SNR values were noticeably improved with the implementation of the NPs.

Area:

Industry ; Nanoparticles

Material:

Leaded brass

Elements:

Lines [nm]:

Pb I 368.35 nm Pb I 405.78 nm

Emmision lines:
Pb I 368.35 nm
Pb I 405.78 nm

Multivariate classification of echellograms: a new perspective in Laser-Induced Breakdown Spectroscopy analysis

Author: Pořízka, P. ; et. al.

Journal: Scientific Reports (2017)

Fundamentals Applications Chemometrics

DOI: 10.1038/s41598-017-03426-0

Authors
Burget, R. ; Kaiser, J. ; Klus, J. ; Mašek, J. ; Modlitbová, P. ; Novotný, J. ; Novotný, K. ; Prochazka, D. ; Rajnoha, M.

Keywords

Laser-Induced Breakdown Spectroscopy; ;

Abstract

In this work, we proposed a new data acquisition approach that significantly improves the repetition rates of Laser-Induced Breakdown Spectroscopy (LIBS) experiments, where high-end echelle spectrometers and intensified detectors are commonly used. The moderate repetition rates of recent LIBS systems are caused by the utilization of intensified detectors and their slow full frame (i.e. echellogram) readout speeds with consequent necessity for echellogram-to-1D spectrum conversion (intensity vs. wavelength). Therefore, we investigated a new methodology where only the most effective pixels of the echellogram were selected and directly used in the LIBS experiments. Such data processing resulted in significant variable down-selection (more than four orders of magnitude). Samples of 50 sedimentary ores samples (distributed in 13 ore types) were analyzed by LIBS system and then classified by linear and non-linear Multivariate Data Analysis algorithms. The utilization of selected pixels from an echellogram yielded increased classification accuracy compared to the utilization of common 1D spectra.

Area:

Geology

Material:

Sedimentary ore

Elements:

Lines [nm]:

Fe I 344.10 nm Fe I 373.71 nm Fe I 374.56 nm Fe I 404.58 nm Fe I 487.21 nm Fe I 489.15 nm Fe I 492.05 nm Fe I 495.76 nm Fe I 643.88 nm Fe II 318.01 nm

Lines [nm]:

Mg I 285.21 nm Mg I 383.23 nm Mg I 383.83 nm Mg I 517.27 nm Mg I 518.36 nm Mg II 279.55 nm Mg II 279.80 nm Mg II 280.27 nm Mg II 293.65 nm

Lines [nm]:

Ca I 422.67 nm Ca I 558.88 nm Ca I 559.45 nm Ca II 393.37 nm Ca II 396.85 nm Ca II 854.21 nm Ca II 866.21 nm

Lines [nm]:

Mn I 353.19 nm Mn I 475.40 nm Mn I 476.24 nm Mn I 478.34 nm Mn I 482.35 nm

Lines [nm]:

Al I 308.22 nm Al I 309.27 nm Al I 394.40 nm Al I 396.15 nm

...

Emmision lines:
Mg II 279.55 nm
Mg II 279.80 nm
Mg II 280.27 nm
Mg I 285.21 nm
Si I 288.16 nm
Mg II 293.65 nm
Al I 308.22 nm
Al I 309.27 nm
Fe II 318.01 nm
Cu I 327.40 nm
Ag I 328.07 nm
Zn I 334.50 nm
Fe I 344.10 nm
Mn I 353.19 nm
Cr I 354.78 nm
Fe I 373.71 nm
Fe I 374.56 nm
Mg I 383.23 nm
Mg I 383.83 nm
Si I 390.55 nm
Ca II 393.37 nm
Al I 394.40 nm
Al I 396.15 nm
Ca II 396.85 nm
Fe I 404.58 nm
Pb I 405.78 nm
Ca I 422.67 nm
Cr I 455.40 nm
Mn I 475.40 nm
Mn I 476.24 nm
Mn I 478.34 nm
Mn I 482.35 nm
Fe I 487.21 nm
Fe I 489.15 nm
Fe I 492.05 nm
Fe I 495.76 nm
Mg I 517.27 nm
Mg I 518.36 nm
Ca I 558.88 nm
Ca I 559.45 nm
Na I 589.00 nm
Na I 589.59 nm
Fe I 643.88 nm
H I 656.28 nm
Li I 670.78 nm
Li I 670.79 nm
K I 766.49 nm
K I 769.90 nm
O I 777.19 nm
Ca II 854.21 nm
Ca II 866.21 nm
N I 868.34 nm

Multivariate approach to the chemical mapping of uranium in sandstone-hosted uranium ores analyzed using double pulse laser-induced breakdown spectroscopy

Author: Klus, J. ; et. al.

Journal: Spectrochimica Acta Part B: Atomic Spectroscopy (2016)

Applications Chemometrics

DOI: 10.1016/j.sab.2016.08.014

Authors
Kaiser, J. ; Mikysek, P. ; Novotný, J. ; Novotný, K. ; Pořízka, P. ; Prochazka, D. ; Prochazková, P. ; Slobodník, M. ; Trojek, T.

Keywords

Laser-Induced Breakdown Spectroscopy; Uranium; principal component analysis; Chemical mapping; Sandstone-hosted deposit; X-ray Fluorescence;

Abstract

The goal of this work is to provide high resolution mapping of uranium in sandstone-hosted uranium ores using Laser-Induced Breakdown Spectroscopy (LIBS) technique. In order to obtain chemical image with highest possible spatial resolution, LIBS system in orthogonal double pulse (DP LIBS) arrangement was employed. Owing to this experimental arrangement the spot size of 50 μm in diameter resulting in lateral resolution of 100 μm was reached. Despite the increase in signal intensity in DP LIBS modification, the detection of uranium is challenging. The main cause is the high density of uranium spectral lines, which together with broadening of LIBS spectral lines overreaches the resolution of commonly used spectrometers. It results in increased overall background radiation with only few distinguishable uranium lines. Three different approaches in the LIBS data treatment for the uranium detection were utilized: i) spectral line intensity, ii) region of apparent background and iii) multivariate data analysis. By utilizing multivariate statistical methods, a specific specimen features (in our case uranium content) were revealed by processing complete spectral information obtained from broadband echelle spectrograph. Our results are in a good agreement with conventional approaches such as line fitting and show new possibilities of processing spectral data in mapping. As a reference technique to LIBS was employed X-ray Fluorescence (XRF). The XRF chemical images used in this paper have lower resolution (approximately 1–2 mm per image point), nevertheless the elemental distribution is apparent and corresponds to presented LIBS experiments.

Area:

Geology ; Industry ; Mapping

Material:

Sandstone

Elements:

Lines [nm]:

U II 409.01 nm

Emmision lines:
U II 409.01 nm

Assessment of the most effective part of echelle laser-induced plasma spectra for further classification using Czerny-Turner spectrometer

Author: Pořízka, P. ; et. al.

Journal: Spectrochimica Acta Part B: Atomic Spectroscopy (2016)

Fundamentals Applications Chemometrics

DOI: 10.1016/j.sab.2016.09.004

Authors
Brada, M. ; Kaiser, J. ; Klus, J. ; Novotný, J. ; Novotný, K. ; Prochazka, D. ; Vítková, G.

Keywords

Laser-Induced Breakdown Spectroscopy; Multivariate classification; Echelle spectrometer; Czerny-Turner spectrometer;

Abstract

The objective of this work was to assess a part of echelle Laser-Induced Plasma spectra (ranging from 200 to 1000 nm) that could be most effectively employed for rocks classification. Therefore, a 60 nm wide spectral window mask was iteratively moved over the broadband echelle spectra. Each created narrow artificial spectral windows (60 nm) was used for the classification of rock samples using various Multivariate Data Analysis (MVDA) algorithms, reaching more than 99% of the overall accuracy in certain cases. Afterwards, the Czerny-Turner spectrometer (having higher sensitivity compared to the echelle spectrometer) was aligned to the a priori selected and the most effective spectral regions and rocks samples were re-measured. Consequently the MVDA analyses were utilized again, providing also satisfying classification results yielding more than 99% of the overall accuracy. Measurements of 28 sedimentary ores (certified reference materials) were done utilizing commercially available X-Trace device (AtomTrace), where spectrometers in both configurations (echelle and Czerny-Turner) were exploited.

Area:

Geology

Material:

Massive sulphide ; Mineralized ultramafic ; Siliceous dolomite ; Siltstone

Elements:

Lines [nm]:

Fe I 302.06 nm Fe I 304.76 nm Fe I 305.74 nm Fe I 404.58 nm Fe I 406.36 nm Fe I 407.17 nm Fe I 423.59 nm Fe I 425.08 nm Fe I 426.05 nm

Lines [nm]:

Mg I 285.21 nm Mg I 383.23 nm Mg I 383.83 nm Mg II 279.55 nm Mg II 280.27 nm

Lines [nm]:

Al I 308.22 nm Al I 309.27 nm Al I 394.40 nm Al I 396.15 nm

Lines [nm]:

Ca I 422.67 nm Ca II 393.37 nm Ca II 396.85 nm

Lines [nm]:

Si I 390.55 nm Si I 288.16 nm

...

Emmision lines:
Mg II 279.55 nm
Mg II 280.27 nm
Mg I 285.21 nm
Si I 288.16 nm
Fe I 302.06 nm
Fe I 304.76 nm
Fe I 305.74 nm
Al I 308.22 nm
Al I 309.27 nm
Cu I 324.75 nm
Cu I 327.40 nm
Mg I 383.23 nm
Mg I 383.83 nm
Si I 390.55 nm
Ca II 393.37 nm
Al I 394.40 nm
Al I 396.15 nm
Ca II 396.85 nm
Fe I 404.58 nm
Fe I 406.36 nm
Fe I 407.17 nm
Ca I 422.67 nm
Fe I 423.59 nm
Fe I 425.08 nm
Fe I 426.05 nm

Effect of experimental parameters and resulting analytical signal statistics in laser-induced breakdown spectroscopy

Author: Klus, J. ; et. al.

Journal: Spectrochimica Acta Part B: Atomic Spectroscopy (2016)

Fundamentals

DOI: 10.1016/j.sab.2016.10.002

Authors
Kaiser, J. ; Novotný, J. ; Novotný, K. ; Pořízka, P. ; Prochazka, D.

Keywords

Laser-induced breakdown spectroscopy; Generalized extreme value distribution; shot-to-shot statistics ;

Abstract

The purpose of this work is to provide detailed study of statistical behavior of different types of analytical signals in typical of Laser-Induced Breakdown Spectroscopy (LIBS) measurements. The main goal of this work is to justify usage of arithmetic mean and standard deviation as statistical estimates of expected value of selected analytical signal. In contrary to the general assumption that LIBS data show Gaussian distribution, this paper deals with the hypothesis that the data rather demonstrate Generalized Extreme Value Distribution. The study is realized on 10 selected lines measured on NIST glass standard. In order to cover wide range of possible applications three different spectra internal standardization techniques and their influence on distribution were studied. Finally, assuming that the data comes from a single distribution and the central limit theorem is valid, the influence of accumulations on the line distribution is examined and discussed. Statistical tools used and described in this paper can be utilized by other researchers to confirm their hypotheses and verify utilization of Gaussian distribution or even novel data processing methods.

Area:

LOD

Material:

Soft borosilicate glass

Elements:

Lines [nm]:

Mg II 279.55 nm Mg II 280.27 nm

Lines [nm]:

Ca II 393.37 nm Ca II 396.85 nm

Lines [nm]:

Na I 589.00 nm

Lines [nm]:

Al I 309.27 nm

Lines [nm]:

Si I 288.16 nm

...

Emmision lines:
Mg II 279.55 nm
Mg II 280.27 nm
Si I 288.16 nm
Al I 309.27 nm
Ca II 393.37 nm
Ca II 396.85 nm
Sr II 421.55 nm
Ba II 493.41 nm
Na I 589.00 nm
K I 766.49 nm

Laser-Induced Breakdown Spectroscopy coupled with chemometrics for the analysis of steel: The issue of spectral outliers filtering

Author: Pořízka, P. ; et. al.

Journal: Spectrochimica Acta Part B: Atomic Spectroscopy (2016)

Fundamentals Applications Chemometrics

DOI: 10.1016/j.sab.2016.08.008

Authors
Hrdlička, A. ; Kaiser, J. ; Képeš, E. ; Klus, J. ; Novotný, J. ; Novotný, K. ; Prochazka, D.

Keywords

Laser-Induced Breakdown Spectroscopy, LIBS; Outlier filtering; Principal Component Analysis, PCA; Linear correlation; Total spectral intensity; Soft Independent Modelling of Class Analogies, SIMCA;

Abstract

In this manuscript we highlight the necessity of outlier filtering prior the multivariate classification in Laser-Induced Breakdown Spectroscopy (LIBS) analyses. For the purpose of classification we chose to analyse BAM steel standards that possess similar composition of major and trace elements. To assess the improvement in figures of merit we compared the performance of three outlier filtering approaches (based on Principal Component Analysis, linear correlation and total spectral intensity) already separately discussed in the LIBS literature. The truncated data set was classified using Soft Independent Modelling of Class Analogies (SIMCA). Yielded results showed significant improvement in the performance of multivariate classification coupled to filtered data. The best performance was observed for the total spectral intensity filtering approach gaining the analytical figures of merit (overall accuracy, sensitivity, and specificity) over 98%. It is noteworthy that the results showed relatively low sensitivity and high specificity of the SIMCA algorithm regardless of the presence of outliers in the data sets. Moreover, it was shown that the variance in the data topology of training and testing data sets has a great impact on the consequent data classification.

Area:

Industry ; Outliers filtering

Material:

Steel

Elements:

Lines [nm]:

Cr II 284.98 nm Cr II 313.21 nm Cr II 336.80 nm Cr I 425.44 nm Cr I 427.48 nm Cr I 428.97 nm Cr I 520.45 nm Cr I 520.60 nm Cr I 520.84 nm Cr I 540.98 nm

Lines [nm]:

Fe I 381.58 nm Fe I 382.04 nm Fe I 382.59 nm Fe I 404.58 nm Fe I 432.58 nm Fe I 438.35 nm Fe I 489.15 nm Fe I 492.05 nm Fe I 495.76 nm

Lines [nm]:

Ni I 341.48 nm Ni I 349.30 nm Ni I 351.51 nm Ni I 352.45 nm

Lines [nm]:

Mn I 403.08 nm

Lines [nm]:

Mo I 550.65 nm

Emmision lines:
Cr II 284.98 nm
Cr II 313.21 nm
Cr II 336.80 nm
Ni I 341.48 nm
Ni I 349.30 nm
Ni I 351.51 nm
Ni I 352.45 nm
Fe I 381.58 nm
Fe I 382.04 nm
Fe I 382.59 nm
Mn I 403.08 nm
Fe I 404.58 nm
Cr I 425.44 nm
Cr I 427.48 nm
Cr I 428.97 nm
Fe I 432.58 nm
Fe I 438.35 nm
Fe I 489.15 nm
Fe I 492.05 nm
Fe I 495.76 nm
Cr I 520.45 nm
Cr I 520.60 nm
Cr I 520.84 nm
Cr I 540.98 nm
Mo I 550.65 nm

Optimization of liquid jet system for laser-induced breakdown spectroscopy analysis

Author: Skočovská, K. ; et. al.

Journal: Review of Scientific Instruments (2016)

Applications

DOI: 10.1063/1.4947233

Authors
Kaiser, J. ; Novotný, J. ; Novotný, K. ; Pořízka, P. ; Prochazka, D.

Keywords

Laser-induced breakdown spectroscopy; Fluid jets; Laser ablation; Copper; Plasma jets;

Abstract

A complex optimization of geometrical and temporal parameters of a jet system (developed in Laser-induced breakdown spectroscopy (LIBS) laboratory of Brno University of Technology) for direct elemental analysis of samples in a liquid state of matter using LIBS was carried out. First, the peristaltic pump was synchronized with the flashlamp of the ablation laser, which reduced variation of the ablated sample amount. Also, the fluctuation of the laser ray angle incident on the jet surface was diminished. Such synchronization reduced signal standard deviations and thus increased repeatability of the measurements. Then, laser energy and distance of the focusing lens from the sample were optimized. The gate delay time and the gate width were optimized for single pulse (SP) experiments; the gate delay time and the inter-pulse delay were optimized for the use of double pulse (DP) variant. Results were assessed according to the highest signal to noise ratios and the lowest relative standard deviations of the signal. The sensitivity of the single pulse and the double pulse LIBS for the detection of heavy metals traces, copper (Cu i at 324.754 nm) and lead (Pb i at 405.781 nm), in aqueous solution of copper (ii) sulfate and lead (ii) acetate, was estimated in terms of limits of detection (LODs). As a result, sensitivity improvement of DP LIBS system was observed, the LOD of Cuobtained with DP was calculated 40% lower than LOD gained from SP technique.

Area:

Instrumentation

Material:

Liquid sample

Elements:

Lines [nm]:

Cu I 324.75 nm

Lines [nm]:

Pb I 405.78 nm

Emmision lines:
Cu I 324.75 nm
Pb I 405.78 nm

Estimating the grade of Mg corrosion using laser-induced breakdown spectroscopy

Author: Pořízka, P. ; et. al.

Journal: Journal of Analytical Atomic Spectrometry (2015)

Applications

DOI: 10.1039/C5JA00257E

Authors
Čelko, L. ; Kaiser, J. ; Klus, J. ; Novotný, K. ; Prochazka, D. ; Ročňáková, I. ; Sládková, L. ; Spotz, Z. ; Šperka, P.

Keywords

Abstract

We present a report on the potential use of the Laser-Induced Breakdown Spectroscopy (LIBS) technique for direct investigation of Mg corrosion and related optimization of the table-top LIBS system. Moreover, the preliminary study to prove the capability of this LIBS technique for the estimation of corrosion grade is given. In order to simulate the real corrosive environment, Mg samples were prepared in a constant climate chamber. We show that the corrosive layer on the sample surface significantly affects the properties of laser–matter interactions, i.e. among other parameters causing the matrix effect. Consequently, the properties and persistence of laser-induced plasmas (LIPs) and their composition, generated on such degraded surfaces, essentially differ. Collected radiation of LIP is then analysed and ratios of ionic to atomic Mg spectral lines are correlated with the grade of magnesium corrosion, i.e. content of Mg(OH)2 on the sample surface. The content of Mg(OH)2 is also correlated with plasma temperature as well as with the electron number density of LIP. Additionally, X-ray diffraction (XRD) analysis and optical profilometry were utilized to obtain more comprehensive information about the degradation grade of high purity Mg samples.

Area:

Industry ; LOD

Material:

High purity magnesium

Elements:

Lines [nm]:

Mg I 309.30 nm Mg I 309.69 nm Mg I 382.94 nm Mg I 383.23 nm Mg I 516.73 nm Mg I 517.27 nm Mg I 518.36 nm Mg I 571.11 nm Mg I 293.67 nm Mg II 293.65 nm Mg II 448.13 nm

Emmision lines:
Mg II 293.65 nm
Mg I 293.67 nm
Mg I 309.30 nm
Mg I 309.69 nm
Mg I 382.94 nm
Mg I 383.23 nm
Mg II 448.13 nm
Mg I 516.73 nm
Mg I 517.27 nm
Mg I 518.36 nm
Mg I 571.11 nm

Algal Biomass Analysis by Laser-Based Analytical Techniques-A Review

Author: Pořízka, P. ; et. al.

Journal: Sensors (2014)

Applications Review

DOI: 10.3390/s140917725

Authors
Adam, V. ; Brada, M. ; Kaiser, J. ; Kizek, R. ; Novotný, J. ; Novotný, K. ; Petrilák, M. ; Pilát, Z. ; Prochazka, D. ; Prochazková, P. ; Samek, O. ; Sládková, L. ; Zemánek, P.

Keywords

Laser-Induced Breakdown Spectroscopy; LIBS; Laser-Ablation Inductively Coupled Plasma coupled with Mass Spectroscopy and Optical Emission Spectroscopy; LA-ICP-MS; LA-ICP-OES; ICP-OES; Raman spectroscopy; algae; algal biomass; biofuel; bioremediation;

Abstract

Algal biomass that is represented mainly by commercially grown algal strains has recently found many potential applications in various fields of interest. Its utilization has been found advantageous in the fields of bioremediation, biofuel production and the food industry. This paper reviews recent developments in the analysis of algal biomass with the main focus on the Laser-Induced Breakdown Spectroscopy, Raman spectroscopy, and partly Laser-Ablation Inductively Coupled Plasma techniques. The advantages of the selected laser-based analytical techniques are revealed and their fields of use are discussed in detail.

Area:

Environment ; Industry ; Nutrition

Material:

Algae ; Biomass

Elements:

Lines [nm]:

H I 656.28 nm H I 486.14 nm

Lines [nm]:

Na I 589.00 nm Na I 589.59 nm

Lines [nm]:

Mg II 279.55 nm Mg II 280.27 nm

Lines [nm]:

K I 766.49 nm K I 769.90 nm

Lines [nm]:

Ca II 393.37 nm Ca II 396.85 nm

Emmision lines:
Mg II 279.55 nm
Mg II 280.27 nm
Ca II 393.37 nm
Ca II 396.85 nm
H I 486.14 nm
Na I 589.00 nm
Na I 589.59 nm
H I 656.28 nm
K I 766.49 nm
K I 769.90 nm

Fast identification of biominerals by means of stand-off laser-induced breakdown spectroscopy using linear discriminant analysis and artificial neural network

Author: Vítková, G. ; et. al.

Journal: Spectrochimica Acta Part B: Atomic Spectroscopy (2012)

Applications Chemometrics

DOI: 10.1016/j.sab.2012.05.010

Authors
Hrdlička, A. ; Kaiser, J. ; Malina, R. ; Novotný, J. ; Novotný, K. ; Prochazka, D. ; Prokeš, L.

Keywords

Stand‐off LIBS; Laser-induced breakdown spectroscopy; PCA; LDA; ANN; Biomineral; Geomaterial; Archaeology;

Abstract

The goal of this paper is to compare two selected statistical techniques used for identification of archeological materials merely on the base of their spectra obtained by stand-off laser-induced breakdown spectroscopy (stand-off LIBS). Data processing using linear discriminant analysis (LDA) and artificial neural networks (ANN) were applied on spectra of 18 different samples, some of them archeological and some recent, containing 7 types of material (i.e. shells, mortar, Brick, soil pellets, ceramic, teeth and bones). As the input data PCA scores were taken. The intended aim of this work is to create a database for simple and fast identification of archeological or paleontological materials in situ. This approach can speed up and simplify the sampling process during archeological excavations that nowadays tend to be quite damaging and time-consuming.

Area:

Archaeology ; Classification ; Cultural heritage

Material:

Bone ; Brick ; Mortar ; Potsherd ; Shell ; Soil ; Tile ; Tooth

Elements:

Emmision lines:

Author: Prochazka, D.

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Co-author: Prochazka, D.

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