Aspects of laser ablation sample introduction for inductively coupled plasma mass spectrometry (ICPMS) have been investigated. For some analytes, nonrepresentative subsampling or fractionation is the major cause of poor analytical accuracy. Fractionation is prevalent for ablation at low laser fluence and with multiple laser pulses incident on the same area of the sample surface. The fluence dependence is explained by the relative depths of the melt- and heat-affected zones. Volatile analyte elements that are segregated in the bulk, or become segregated as the ablation zone is heated, are most prone to fractionation. For metal alloys, the extent of fractionation can be qualitatively predicted from the binary-phase diagram of the corresponding analyte matrix. Analysis by Auger electron spectroscopy showed that miscible elements may also be segregated at the near surface, with the extent of segregation growing with multiple laser pulses. Such segregation results in increased fractionation.

Techniques for semiquantitative analysis of solid materials by laser ablation sample introduction for inductively coupled plasma mass spectrometry (ICPMS) are investigated. Under some ablation conditions, nonrepresentative subsampling or fractionation is a major source of analytical error, particularly for samples that have relatively low melting or boiling point components, Use of high laser fluence and reduced spatial overlap of laser pulses on the sample surface was found to reduce fractional ablation. improved analytical results were obtained by calibration with aqueous solution standards using two-channel sample introduction to give equivalent ICP conditions for ablated material and a solution standard, This method has a further advantage of not requiring solid reference standards, Semiquantitative analysis results for steel and glass SRMs obtained under matched plasma conditions are discussed.

We have investigated the entrainment in a jet expansion of material vaporized with a laser pulse from a surface below but closely adjacent to the jet orifice. Jets of He and Ar were used as carriers, and perylene was the test substance. Its distribution in space and time far from the nozzle was measured by laser-induced fluorescence and one-dimensional imaging with an optical multichannel analyzer. The width of the perylene concentration profile was found to be much narrower than the width of the gas expansion, especially in He. This makes it possible to extract a useful portion of the entrained material through a skimmer. Depending on the values of experimental parameters, the center of the profile first appears above, on, or below the jet axis and then moves lower with time. Effects of several parameters on shape and time-dependent position of the profile were investigated. The results can be used to optimize the overlap of the concentration pulse with a skimmer or other probe.

Several cell designs have been systematically evaluated for gas flow entrainment and transport of laser ablated material to a secondary excitation source for elemental analysis. The best cell is not limited to samples of particular size or shape and is insensitive to sample surface irregularity. An annular gas sheath around the cell results in a transient response sufficiently fast to permit depth and lateral sampling of single samples or rapid throughput of different samples but slow enough to give a steady signal with laser repetition rates ≥10 Hz. Entrainment and transport of ablated particulates have been investigated experimentally and by model calculation for a test material (Mo metal). The equations for predicting diffusive and gravitational loss of particles in a horizontal tube are presented and discussed. The major loss mechanism appears to be gravitational deposition of relatively large particles formed during ablation and possibly by coalescence within the transfer tube. Entrainment of ablated Mo by the cell and mass transport from the cell to the secondary source were determined to be ∼90% and ∼40% efficient, respectively. Shot-to-shot fluctuation in particle size may cause corresponding variation in transport efficiency when the upper end of the ablated particle size distribution exceeds the size limit for particle transport.

Using laser‐induced fluorescence as the probe and perylene as the test substance, we have measured the distribution in space and time of material injected into a jet expansion by laser‐induced desorption from a surface near the jet orifice. The results can be used to optimize the overlap of the concentration pulse with a skimmer or other sampling device.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSample analysis using plasma source mass spectrometry with electrochemical sample introductionC. J. Park, Jon C. Van Loon, Peter. Arrowsmith, and J. B. FrenchCite this: Anal. Chem. 1987, 59, 17, 2191–2196Publication Date (Print):September 1, 1987Publication History Published online1 May 2002Published inissue 1 September 1987https://pubs.acs.org/doi/10.1021/ac00144a039https://doi.org/10.1021/ac00144a039research-articleACS PublicationsRequest reuse permissionsArticle Views92Altmetric-Citations71LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts