Laser Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a simple spark spectrochemical sensor technology in which a laser beam is directed at a sample to create a high-temperature microplasma. A spectrometer/array detector is used to disperse the light emission and detect its intensity at specific wavelengths. Laser induced breakdown spectroscopy has many attributes that make it an attractive tool for chemical analysis. A recent breakthrough in component development, the commercial launching of a small, high-resolution spectrometer, has greatly expanded the utility of laser induced breakdown spectroscopy and resulted in a new potential for field-portable broadband laser induced breakdown spectroscopy because the technique is now sensitive simultaneously to all chemical elements due to detector response in the 200 to 980 nm range with 0.1 nm spectral resolution. Other attributes include: (a) small size and weight; (b) technologically mature, inherently rugged, and affordable components; (c) in-situ analysis with no sample preparation required; (d) inherent high sensitivity; (e) real-time response; and (f) point sensing or standoff detection. Laser induced breakdown spectroscopy sensor systems can be used to detect and analyze target samples by identifying all constituent elements and by determining either their relative or absolute abundances.

Laser-based spectroscopic techniques are beginning to emerge as important tools for chemical analysis because of the prospect they offer for the selective, minimally destructive, and high sensitivity detection and analysis of solid, liquid, aerosol, and gaseous materials in real time. Laser-induced breakdown spectroscopy is one such technique. Laser induced breakdown spectroscopy is not a new technique: early laser-induced breakdown studies go back to the early 1960s and important application studies date from the. A comprehensive review of laser induced breakdown spectroscopy development and applications through the mid-1990s were produced by rusak et al. (1997). Recently, laser induced breakdown spectroscopy has received renewed attention because of its simple and direct nature, which make it an optimal technology for use as a real-time, field-portable sensor.

Laser induced breakdown spectroscopy uses a pulsed laser to create a spark. The technique has many attributes that make it an attractive tool for chemical analysis, particularly regarding its potential as a field-portable sensor for geochemical analysis. Laser induced breakdown spectroscopy is relatively simple and straightforward, so skilled analysts are not required. Little to no sample preparation is required, which eliminates the possibility of adulteration of the sample through improper handling or storage or cross-contamination during sample preparation. Laser induced breakdown spectroscopy provides a real-time response and simultaneous multielement detection and analysis. The laser plasma is formed over a very limited spatial area, so that only a very small amount of sample (picograms to nanograms) is engaged in each laser microplasma event. All components of the instrument can be made small and rugged for field use and laser induced breakdown spectroscopy sensors can be operated either as a point sensor or in a standoff detection mode. The detection limits of laser induced breakdown spectroscopy are in the low hundreds to tens of ppm range for most common elements, so field-portable laser induced breakdown spectroscopy should be capable of field surveying and screening for the geochemical exploration and environmental remediation applications envisaged.

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