nanosecond transversely excited atmospheric carbon dioxide laser (TEA CO2); laser-induced breakdown spectroscopy; quantitative analysis; cast iron;ND-YAG LASER; INDUCED PLASMA; SPECTROCHEMICAL ANALYSIS; QUANTITATIVE-ANALYSIS; METALLIC MATRICES; STEEL; SAMPLES; UNIVARIATE; PARAMETERS; SINGLE

The analytical capability of laser-produced plasma for the analysis of low alloying elements in cast iron samples has been investigated. The plasma was induced by irradiation of a sample in air at atmospheric pressure using an infrared CO2 laser. Emission spectra were recorded by time-integrated spatially-resolved measurement technique. A set of ten cast iron samples in a powder or particulate form were provided by BAM (Bundesanstalt fur Material Forschung und Prufung, Deutschland), seven of which were used for calibration, and three were treated as unknowns. Linear calibration curves were obtained for copper, chromium, and nickel, with correlation coefficients above 0.99. Precision and accuracy of the LIBS method was evaluated and compared to those obtained by the inductively coupled plasma (ICP) analysis of the same samples. Detection limits for Cu, Cr and Ni were close to those reported in the literature for other comparable iron-based alloys obtained using different LIBS systems. Analytical figures of merit of the studied LIBS system may be considered as satisfying, especially in the light of other advantages of the method, like cost effective and fast analysis with no sample preparation, and with a possibility for real-time on-site analysis.

INDUCED BREAKDOWN SPECTROSCOPY; SPECTROCHEMICAL ANALYSIS; GEOLOGICAL SAMPLES; ROCKS; OPTIMIZATION; EMISSION; METALS; ORIGIN; PULSES; MARS

We present a study of the plasma generated by transversely excited atmospheric (TEA) CO2 laser irradiation of a basalt sample. The plasma was induced in air at atmospheric pressure. The same sample was also analyzed using a commercial LIBS system based on Nd:YAG laser and time-gated detection. The main plasma parameters, temperature, and electron number density were determined and analytical capabilities of the two systems compared. Despite differences in laser wavelength, pulse duration, applied fluence, and signal detection scheme, the two systems are comparable in terms of element detectability and limits of detection. In both cases, all elements usually present in geological samples were identified. The estimated limits of detection for most elements were below 100 ppm, while for Cu, Cr, and Sr they were around or below 10 ppm. The obtained results led to the conclusion that simple, cost- effective TEA CO2 LIBS system can find applications for geological explorations.

Laser Induced Breakdown Spectroscopy (LIBS); Transversely excited atmospheric carbondioxide (TEA CO2) laser; Aluminum alloys; Qualitative analysis; Quantitative analysis;INDUCED GAS PLASMA; SPECTROCHEMICAL ANALYSIS; QUANTITATIVE-ANALYSIS; OPTICAL-EMISSION; LIBS; SAMPLES; PULSES; SPECTROMETRY; METALS; AIR

The applicability of nanosecond infrared Transversely Excited Atmospheric (TEA) CO2 laser induced plasma for spectrochemical analysis of aluminum alloys was investigated. The plasma was generated by focusing a pulsed TEA CO2 laser that emits at 10.6 mu m on the Al target in ambient air at atmospheric pressure. The temporal profile of the laser pulse is composed of a 100 ns peak followed by a slowly decaying tail of about 2 mu s. The output pulse energy was approximately 160 mJ, thus the peak output power was estimated to be around 1.6 MW. Time-Integrated Space-Resolved Laser Induced BreakdownSpectroscopy (TISR-LIBS) was employed to obtain the emission spectra. The maximum intensity of emission, with sharp and well resolved spectral lines that were almost free of the background continuum, was obtained from plasma region 2 mm from the target surface. Linear calibration curves for Mg, Cr, Cu and Fe were obtained using aluminum alloy spectrochemical standards. The limits of detection for the investigated elements were in the 2-73 ppm range. Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) was used as a reference technique to estimate the accuracy of LIBS determination by use of control samples with known compositions. Comparison of the obtained results with those available in the literature confirms that LIBS system based on TEA CO2 laser, in combination with TISR spectral measurements, can be successfully applied to qualitative and quantitative determinations of minor elements in aluminum based alloys. (C) 2017 Elsevier B.V. All rights reserved.

Laser-induced breakdown spectroscopy (LIES); Transversely excited atmospheric carbon dioxide (TEA CO2) laser; Powdered organic samples; Spirulina; Quantitative analysis;INDUCED BREAKDOWN SPECTROSCOPY; INDUCED GAS PLASMA; PLANT MATERIALS; QUANTITATIVE-ANALYSIS; LIBS; EMISSION; MICRONUTRIENTS; OPTIMIZATION; SPECTROMETRY; CO2-LASER

The aim of this study was to develop a simple laser induced breakdown spectroscopy (LIBS) method for quantitative elemental analysis of powdered biological materials based on laboratory prepared calibration samples. The analysis was done using ungated single pulse LIBS in ambient air at atmospheric pressure. Transversely-Excited Atmospheric pressure (TEA) CO2 laser was used as an energy source for plasma generation on samples. The material used for the analysis was a blue-green alga Spirulina, widely used in food and pharmaceutical industries and also in a few biotechnological applications. To demonstrate the analytical potential of this particular LIBS system the obtained spectra were compared to the spectra obtained using a commercial LIBS system based on pulsed Nd:YAG laser. A single sample of known concentration was used to estimate detection limits for Ba, Ca, Fe, Mg, Mn, Si and Sr and compare detection power of these two LIES systems. TEA CO2 laser based LIES was also applied for quantitative analysis of the elements in powder Spirulina samples. Analytical curves for Ba, Fe, Mg, Mn and Sr were constructed using laboratory produced matrix-matched calibration samples. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used as the reference technique for elemental quantification, and reasonably well agreement between ICP and LIBS data was obtained. Results confirm that, in respect to its sensitivity and precision, TEA CO2 laser based LIBS can be successfully applied for quantitative analysis of macro and micro-elements in algal samples. The fact that nearly all classes of materials can be prepared as powders implies that the proposed method could be easily extended to a quantitative analysis of different kinds of materials, organic, biological or inorganic. (C) 2017 Elsevier B.V. All rights reserved.