Laser Spark Emission Spectrometry

From the beginning of the 60s to the end of the 2000s, there was no established term in the English literature for the method name: laser spark spectroscopy or laser induced spark spectrocopy, Laser-Induced Plasma Spectroscopy and Laser-Induced Breakdown Spectroscopy . By the end of the 2000s, in the process of discussing terminology, Laser-Induced Breakdown Spectroscopy was chosen. This choice is associated with a more “favorable” abbreviation LIBS as a keyword for searching in scientific and publicly available indexing systems (a search using the abbreviation LIPS gives results related to perfumery). In the Russian-language literature, there is still no generally accepted name: Laser-spark emission spectrometry, laser-induced plasma spectroscopy , laser-atomic emission spectroscopy.

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A laser breakdown is formed when focusing pulsed laser radiation on the surface of a sample (or in a volume of gas - for example, in air). The process of creating a plasma by laser irradiation of the surface of a sample is called laser ablation .

Currently, LIES is rapidly developing due to the possibility of creating universal emission analyzers capable of analyzing any types of samples (including microscopic) for all elements at once, with excellent spatial resolution on the surface, and without contact, without touching the samples themselves (distant objects), without which or sample preparation (in the case of a homogeneous chemical composition of the material) working in real time in a compact portable version.

A very hot plasma is formed in the laser spark (up to 40 thousand kelvin at an electron concentration of up to ~ 10 ¹⁸ cm ⁻³ ). In this case, the plasma of a torch extracted from completely different samples often has similar characteristics.

The use of femtosecond laser pulses (shorter than 1000 fs) greatly simplifies the process of instant evaporation and ionization of a substance without affecting heat transfer along the sample volume and screening of laser radiation with a torch plasma, the formation of which occurs after the end of the laser pulse. These factors improve the reproducibility of the analysis.

The use of ultraviolet lasers allows for better efficiency and reproducibility of laser ablation and, therefore, higher analysis accuracy than is achievable with less complex and more common infrared lasers.

In practical applications, the greatest difficulties are caused by calibration problems and not impressive definition limits (about 10 ⁻³ % with a relative error of 5–10%). In many cases, graduation remains only approximate. In cases of analysis of materials representing heterogeneous mixtures of substances (for example, ores and metallurgical mixtures), laborious sample preparation is necessary.

In order to reduce the limits of determination, double laser pulses are sometimes used in LIBS. Ideally, the first short ultraviolet pulse produces laser extraction (a torch is created), and the second, longer, infrared pulse produces additional heating of the torch plasma.

The laser spark plasma can be used not only as a source of emission spectra, but also as an atomizer- ionizer for mass spectrometric registration of ions. This is another method - laser-spark mass spectrometry (LIMS), or laser micro-mass spectrometry . Usually, time-of-flight mass spectrometers are used in the LIMS method so that the pulsed nature of the laser spark is combined with pulsed ion extraction.

• Spectroscopy
• Atomic emission spectroscopy
• Quantitative analysis
• Emission spectrum
• Analytical chemistry - classification of analysis methods

• http://www.anchem.ru/ - portal of analytical chemists
• The prospects of analytical atomic spectrometry are the development trends of the five main branches of atomic spectrometry: absorption, emission, mass spectrometric, fluorescence and ionization (request the authors by e-mail: view email ).
• Chemical encyclopedia
• V. Kopachevsky, V. Spector, D. Klemyato, V. Boykov, M. Krivosheeva, L. Bobrova. "Quantitative analysis of the composition of container glass with the LEA S500 analyzer" "Photonics" 2008, 1
• Laser atomic emission spectroscopy and analysis equipment