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Shape and size of aerosols influences ICP-MS performance.

Laser Induced breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a well-established technique for the elemental analysis of solid samples based on spectral analysis of atomic emission from laser induced plasma, obtained by focusing a pulsed laser beam on the sample. LIBS has been studied and developed for its unique advantages of rapid, in situ, multi-element analysis. LIBS can be used for fast compositional analysis of solids, liquids, gases and aerosols. The potential applications include detectors for hazardous materials (biological and chemical agents, etc.), forensic analysis at crime scenes, environmental monitoring and space exploration. Moreover, this technique has relatively low cost and the possibility to build portable instruments that allow real field analysis.

Laser Ablation Inductively-Coupled-Plasma Mass-Spectroscopy (LA-ICP-MS)

Laser ablation optical and mass spectrometry with inductively coupled plasma (LA-ICP-AES/MS) appears to be the only analytical approach for nearly non-destructive determination of a large number of elements with very low detection limits.

Significant improvements in this technology have been achieved through systematic studies of experimental parameters, including laser wavelength, pulse duration, laser energy, and gas ambient. The primary goal of these studies has been to improve chemical analysis performance, by increasing precision, accuracy and eliminating fractionation. These figures of merit are influenced by the ablated aerosol particle size distribution. Chemical composition, entrainment, transport, and decomposition in the ICP, all are related to the size distribution of the aerosol particles.

Laser ablation optical and mass spectrometry with inductively coupled plasma schematic.

We have utilized our understanding of laser ablation processes to improve analytical performance of this technology. Knowledge gained from the fundamental studies points to the use of short pulse lasers for producing ideal conditions for ICP-MS measurements; small particles with narrow size distribution. Femtosecond ablation provides the plasma-plume conditions for producing this behavior. Our work emphasized the investigation of femtosecond laser ablation into an Inductively Coupled Plasma-(quadrupole or time-of-flight)-Mass Spectrometer as a way of studying laser material interaction for improving chemical analysis.