Laser ablation in analytical chemistry—a review

Abstract

Laser ablation is becoming a dominant technology for direct solid sampling in analytical chemistry. Laser ablation refers to the process in which an intense burst of energy delivered by a short laser pulse is used to sample (remove a portion of) a material. The advantages of laser ablation chemical analysis include direct characterization of solids, no chemical procedures for dissolution, reduced risk of contamination or sample loss, analysis of very small samples not separable for solution analysis, and determination of spatial distributions of elemental composition. This review describes recent research to understand and utilize laser ablation for direct solid sampling, with emphasis on sample introduction to an inductively coupled plasma (ICP). Current research related to contemporary experimental systems, calibration and optimization, and fractionation is discussed, with a summary of applications in several areas.

Laser Induced Breakdown Spectroscopy

“…24,[72][73][74] As a result, a UV laser pulse favors higher increasing rates of surface temperature and higher maximum surface temperatures (higher energy reaching the sample surface) and an IR laser pulse allows higher maximum plasma temperatures, higher maximum electron densities and higher plasma expansion (higher energy absorption by the plasma and greater laser-plasma interaction). 75,78 This leads, in general, to a higher ablation efficiency (amount of mass removed per unit energy delivered) and reproducibility, a lower fractionation and a lower background continuum emission when using UV lasers, as described by several papers, 27,[76][77][78][79] and lower threshold fluences (minimum fluence to achieve ablation or a measurable emission signal) when using IR lasers, as described by Cabalín and Laserna 80 in the analysis of different metals and by Gómez et al 81 in a study of removing graffitis from urban buildings. They also reported lower matrix effects due to different melting points of the metal samples and a higher removal efficiency of graffitis when using IR lasers in comparison with UV lasers.…”

“…27 It limits the amount of constituents (analytes) that will be detached from the sample by the laser pulse and introduced into the Figure 2. Sequence of events following the striking of a focused short laser pulse (ca.…”

Seasonal trace-element and stable-isotope variations in a Chinese speleothem: The potential for high-resolution paleomonsoon reconstruction

“…The results presented in this study represent the average of 3 laser ablation passes following pre-cleaning by a previous laser ablation scan. For the purpose of this study, we chose not to use a laser ablation standard due to the difficulties of obtaining matrix-matched traceelement standards and the strong matrix dependence of laser-fractionation [25,26]. Instead, Mg/Ca and Sr/Ca ratios were calculated directly from measured ion-beam intensities (corrected for isotopic abundance).…”

Thin films of ruthenium phthalocyanine complexes

“…The sample material is vaporized in a focused laser beam and transported with argon gas into the inductively coupled plasma ion source of an ICP-MS. The technique offers several advantages including little or no sample preparation and no solvent interferences, and importantly is able to give information about spatial distributions of elemental profiles [13]. This technique, coupled with scanning tunneling microscopy (STM) and a solution-phase ICP-MS technique allows for a detailed investigation of the coverage of surface-bound molecules.…”