TY - JOUR A1 - Hoehse, M. A1 - Paul, Andrea A1 - Gornushkin, Igor B. A1 - Panne, Ulrich T1 - Multivariate classification of pigments and inks using combined Raman spectroscopy and LIBS N2 - The authenticity of objects and artifacts is often the focus of forensic analytic chemistry. In document fraud cases, the most important objective is to determine the origin of a particular ink. Here, we introduce a new approach which utilizes the combination of two analytical methods, namely Raman spectroscopy and laser-induced breakdown spectroscopy (LIBS). The methods provide complementary information on both molecular and elemental composition of samples. The potential of this hyphenation of spectroscopic methods is demonstrated for ten blue and black ink samples on white paper. LIBS and Raman spectra from different inks were fused into a single data matrix, and the number of different groups of inks was determined through multivariate analysis, i.e., principal component analysis, soft independent modelling of class analogy, partial least-squares discriminant analysis, and support vector machine. In all cases, the results obtained with the combined LIBS and Raman spectra were found to be superior to those obtained with the individual Raman or LIBS data sets. KW - Pigments KW - Raman KW - LIBS KW - Chemometrics PY - 2012 DO - https://doi.org/10.1007/s00216-011-5287-6 SN - 1618-2642 SN - 1618-2650 VL - 402 IS - 4 SP - 1443 EP - 1450 PB - Springer CY - Berlin AN - OPUS4-25440 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Shabanov, Sergej V. A1 - Panne, Ulrich T1 - Abel inversion applied to a transient laser induced plasma: implications from plasma modeling N2 - We test the effects of non-uniformity, non-transparency, and non-stationarity of a laser-induced plasma on the results obtained by the Abel inversion method. The method is commonly used for obtaining spatially resolved emissivity of axially symmetric non-homogeneous radiating objects. Besides the axial symmetry, the plasma is assumed to be optically thin. As the method addresses a certain plasma state, the plasma is required to be stationary during measurements. It is difficult to satisfy the aforementioned conditions for transient laser induced plasmas. As such the plasmas are not stationary; they have steep gradients of thermodynamic parameters that rapidly vary during the plasma evolution. Therefore, any conclusion based on time-integrated measurements and the corresponding data processing should account for these effects. In this work, we use the collision-dominated plasma model to generate time- and spatially resolved synthetic spectra. The spectra are processed by executing the Abel inversion using two numerical algorithms. Thus obtained spatially resolved plasma parameters (emissivity, temperature, and number density) are compared with the exact parameters used to set up the model. In doing so, the accuracy of the Abel inversion method is assessed. Special attention is paid to the dynamic aspect of the expanding plasma and possible errors which result from time-integrated measurements. PY - 2011 DO - https://doi.org/10.1039/c1ja10044k SN - 0267-9477 SN - 1364-5544 VL - 26 IS - 7 SP - 1457 EP - 1465 PB - Royal Society of Chemistry CY - London AN - OPUS4-25824 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Eschlböck-Fuchs, S. A1 - Huber, N. A1 - Ahamer, C. M. A1 - Hechenberger, J. G. A1 - Kolmhofer, P. J. A1 - Heitz, J. A1 - Rössler, R. A1 - Demidov, Alexander A1 - Schmid, Thomas A1 - Gornushkin, Igor B. A1 - Panne, Ulrich A1 - Pedarnig, J. D. T1 - Application of laser-induced breakdown spectroscopy for the analysis of slags in industrial steel production N2 - Laser-induced breakdown spectroscopy (LIBS) is a fast and versatile technique for (semi) quantitative element analysis of solids, liquids, gases, and particulate matter. The LIBS method is used for optical sensing in various branches of industrial production. In the contribution we review some of our recent results on LIBS analysis of slags from secondary metallurgy in industrial steel making. Major oxides in steel slags are measured at-line and after homogenization using a calibration-free (CF) method. Two approaches for CF analysis based on the Boltzmann plot method and on the calculation of synthetic spectra are compared for the analysis of quaternary oxides. We also present the research in cooperation with our industrial partners in the process-analytical chemistry network PAC. T2 - 11. Kolloquium Arbeitskreis Prozessanalytik CY - Vienna, Austria DA - 30.11.2015 KW - Laser-induced breakdown spectroscopy (LIBS) KW - Process analytical technology KW - Steel slag PY - 2015 PB - Plandruck+ Gesellschaft m.b.H. CY - Wien AN - OPUS4-39005 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bierstedt, Andreas A1 - Kersten, H. A1 - Glaus, Reto A1 - Gornushkin, Igor B. A1 - Panne, Ulrich A1 - Riedel, Jens T1 - Characterization of an airborne laser-spark ion source for ambient mass spectrometry N2 - An airborne laser plasma is suggested as an ambient ion source for mass spectrometry. Its fundamental physical properties, such as an excellent spatial and temporal definition, high electron and ion densities and a high effective cross section in maintaining the plasma, make it a promising candidate for future applications. For deeper insights into the plasma properties, the optical plasma emission is examined and compared to mass spectra. The results show a seemingly contradictory behavior, since the emitted light reports the plasma to almost entirely consist of hot elemental ions, while the corresponding mass spectra exhibit the formation of intact molecular species. Further experiments, including time- resolved shadowgraphy, spatially resolved mass spectrometry, as well as flow-dependent emission spectroscopy and mass spectrometry, suggest the analyte molecules to be formed in the cold plasma vicinity upon interaction with reactive species formed inside the hot plasma center. Spatial separation is maintained by concentrically expanding pressure waves, inducing a strong unidirectional diffusion. The accompanying rarefaction inside the plasma center can be compensated by a gas stream application. This replenishing results in a strong increase in emission brightness, in local reactive species concentration, and eventually in direct mass spectrometric sensitivity. To determine the analytical performance of the new technique, a comparison with an atmospheric pressure chemical ionization (APCI) source was conducted. Two kitchen herbs, namely, spearmint and basil, were analyzed without any sample pretreatment. The presented results demonstrate a considerably higher sensitivity of the presented laser-spark ionization technique. KW - Laser-spark KW - Laser induced plasma KW - Ambient mass spectrometry KW - Optical emission spectroscopy KW - Ionization PY - 2017 DO - https://doi.org/10.1021/acs.analchem.6b04178 SN - 0003-2700 SN - 1520-6882 VL - 89 IS - 6 SP - 3437 EP - 3444 PB - American Chemical Society CY - Washington, DC, USA AN - OPUS4-39474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Shabanov, Sergej V. A1 - Merk, Sven A1 - Tognoni, E. A1 - Panne, Ulrich T1 - Effects of non-uniformity of laser induced plasma on plasma temperature and concentrations determined by the Boltzmann plot method: implications from plasma modeling PY - 2010 DO - https://doi.org/10.1039/C0JA00016G SN - 0267-9477 SN - 1364-5544 VL - 25 SP - 1643 EP - 1653 PB - Royal Society of Chemistry CY - London AN - OPUS4-22942 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Höhse, Marek A1 - Gornushkin, Igor B. A1 - Merk, Sven A1 - Panne, Ulrich T1 - Assessment of suitability of diode pumped solid state lasers for laser induced breakdown and Raman spectroscopy N2 - The potential of a diode pumped solid state (DPSS) laser for laser induced breakdown spectroscopy (LIBS) and Raman spectroscopy was investigated. The DPSS laser operating at repetition rates of 1 Hz–200 kHz, pulse energy of ~1 mJ, and pulse duration of ~20 ns was added to a conventional LIBS system equipped with the flashlamp-pumped Nd:YAG laser (10 Hz, 400 mJ, 6 ns) to directly compare the two laser systems. Despite the lower mass ablated per laser pulse (~several nanograms) and a weaker plasma, the total mass ablated per measurement interval (~1 s) and total emission signal were significantly higher than those obtained with the flashlamp pumped Nd:YAG laser. This resulted in the improved signal-to-noise ratio and better limits of detection (LOD). The best LODs were obtained for Cu, Cr and Ni in ultrapure standard iron samples, 0.7 ppm, 1 ppm and 5 ppm, correspondingly. The plasma from the DPSS laser was characterized in terms of its radiative properties, temperature, and shockwave propagation speed. The suitability of this laser for LIBS-Raman was demonstrated by mapping the elemental and molecular composition of a mineral sample. The results strongly imply that DPSS lasers are the promising source for LIBS, Raman, or combined LIBS-Raman spectroscopy. PY - 2011 DO - https://doi.org/10.1039/c0ja00038h SN - 0267-9477 SN - 1364-5544 VL - 26 IS - 2 SP - 414 EP - 424 PB - Royal Society of Chemistry CY - London AN - OPUS4-22943 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Höhse, Marek A1 - Mory, D. A1 - Florek, S. A1 - Weritz, Friederike A1 - Gornushkin, Igor B. A1 - Panne, Ulrich T1 - A combined laser-induced breakdown and Raman spectroscopy Echelle system for elemental and molecular microanalysis N2 - Raman and laser-induced breakdown spectroscopy is integrated into a single system for molecular and elemental microanalyses. Both analyses are performed on the same ~ 0.002 mm² sample spot allowing the assessment of sample heterogeneity on a micrometric scale through mapping and scanning. The core of the spectrometer system is a novel high resolution dual arm Echelle spectrograph utilized for both techniques. In contrast to scanning Raman spectroscopy systems, the Echelle-Raman spectrograph provides a high resolution spectrum in a broad spectral range of 200-6000 cm- 1 without moving the dispersive element. The system displays comparable or better sensitivity and spectral resolution in comparison to a state-of-the-art scanning Raman microscope and allows short analysis times for both Raman and laser induced breakdown spectroscopy. The laser-induced breakdown spectroscopy performance of the system is characterized by ppm detection limits, high spectral resolving power (15,000), and broad spectral range (290-945 nm). The capability of the system is demonstrated with the mapping of heterogeneous mineral samples and layer by layer analysis of pigments revealing the advantages of combining the techniques in a single unified set-up. KW - LIBS KW - Raman KW - Echelle KW - Laser-induced breakdown spectroscopy KW - Hyphenated technique PY - 2009 DO - https://doi.org/10.1016/j.sab.2009.09.004 SN - 0584-8547 SN - 0038-6987 VL - 64 IS - 11-12 SP - 1219 EP - 1227 PB - Elsevier CY - Amsterdam AN - OPUS4-20493 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Panne, Ulrich A1 - Winefordner, J. D. T1 - Linear correlation for identification of materials by laser induced breakdown spectroscopy: Improvement via spectral filtering and masking N2 - The purpose of this work is to improve the performance of a linear correlation method used for material identification in laser induced breakdown spectroscopy. The improved correlation procedure is proposed based on the selection and use of only essential spectral information and ignoring empty spectral fragments. The method is tested on glass samples of forensic interest. The 100% identification capability of the new method is demonstrated in contrast to the traditional approach where the identification rate falls below 100% for many samples. KW - Correlation analysis KW - Linear correlation KW - Material identification KW - Laser induced plasma KW - LIBS PY - 2009 DO - https://doi.org/10.1016/j.sab.2009.07.038 SN - 0584-8547 SN - 0038-6987 VL - 64 IS - 10 SP - 1040 EP - 1047 PB - Elsevier CY - Amsterdam AN - OPUS4-20621 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Smith, B.W. A1 - Panne, Ulrich A1 - Omenetto, N. T1 - Laser-induced breakdown spectroscopy combined with spatial heterodyne spectroscopy N2 - A spatial heterodyne spectrometer (SHS) is tested for the first time in combination with laser-induced breakdown spectroscopy (LIBS). The spectrometer is a modified version of the Michelson interferometer in which mirrors are replaced by diffraction gratings. The SHS contains no moving parts and the gratings are fixed at equal distances from the beam splitter. The main advantage is high throughput, about 200 times higher than that of dispersive spectrometers used in LIBS. This makes LIBS-SHS a promising technique for low-light standoff applications. The output signal of the SHS is an interferogram that is Fourier-transformed to retrieve the original plasma spectrum. In this proof-of-principle study, we investigate the potential of LIBS-SHS for material classification and quantitative analysis. Brass standards with broadly varying concentrations of Cu and Zn were tested. Classification via principal component analysis (PCA) shows distinct groupings of materials according to their origin. The quantification via partial least squares regression (PLS) shows good precision (relative standard deviation , 10%) and accuracy (within 6 5% of nominal concentrations). It is possible that LIBS-SHS can be developed into a portable, inexpensive, rugged instrument for field applications. KW - Spatial heterodyne spectroscopy KW - Laser-induced breakdown spectroscopy KW - Fourier transform spectroscopy KW - LIBS KW - Laser-induced plasma KW - Interferometry PY - 2014 DO - https://doi.org/10.1366/14-07544 SN - 0003-7028 SN - 1943-3530 VL - 68 IS - 9 SP - 1076 EP - 1084 PB - Society for Applied Spectroscopy CY - Frederick, Md. AN - OPUS4-32163 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Porizka, Pavel A1 - Demidov, Alexandr A1 - Kaiser, J. A1 - Keivanian, J. A1 - Gornushkin, Igor B. A1 - Panne, Ulrich A1 - Riedel, Jens T1 - Laser-induced breakdown spectroscopy for in situ qualitative and quantitative analysis of mineral ores N2 - In this work, the potential of laser-induced breakdown spectroscopy (LIBS) for discrimination and analysis of geological materials was examined. The research was focused on classification of mineral ores using their LIBS spectra prior to quantitative determination of copper. Quantitative analysis is not a trivial task in LIBS measurement because intensities of emission lines in laser-induced plasmas (LIP) are strongly affected by the sample matrix (matrix effect). To circumvent this effect, typically matrix-matched standards are used to obtain matrix-dependent calibration curves. If the sample set consists of a mixture of different matrices, even in this approach, the corresponding matrix has to be known prior to the downstream data analysis. For this categorization, the multielemental character of LIBS spectra can be of help. In this contribution, a principal component analysis (PCA) was employed on the measured data set to discriminate individual rocks as individual matrices against each other according to their overall elemental composition. Twenty-seven igneous rock samples were analyzed in the form of fine dust, classified and subsequently quantitatively analyzed. Two different LIBS setups in two laboratories were used to prove the reproducibility of classification and quantification. A superposition of partial calibration plots constructed from the individual clustered data displayed a large improvement in precision and accuracy compared to the calibration plot constructed from all ore samples. The classification of mineral samples with complex matrices can thus be recommended prior to LIBS system calibration and quantitative analysis. KW - Laser-induced breakdown spectroscopy KW - LIBS KW - Chemometrics KW - Principal component analysis KW - Geochemical analysis PY - 2014 DO - https://doi.org/10.1016/j.sab.2014.08.027 SN - 0584-8547 SN - 0038-6987 VL - 101 SP - 155 EP - 163 PB - Elsevier CY - Amsterdam AN - OPUS4-32588 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -