Laser microprobe mass spectrometry

R. W. Odom and B. Schueler. Laser Microprobe Mass Spectrometry Ion and Neutral Analysis, in Lasers and Mass Spectrometry (D. M. Lubman, ed.) Oxford University Press, Oxford, 1990. Presents a useful discussion of LIMS instrumental issues, including the post-ablation ionization technique. Several anal)n ical applications are presented. 

Laser Ionization Mass Spectrometry Laser Microprobe Mass Analysis Laser Microprobe Mass Spectrometry Laser Ionization Mass Analysis Nonresonant Multi-Photon Ionization... 

KF Karl Fischer (coulometry) LMMS Laser microprobe mass spectrometry... 

LASER MICROPROBE MASS SPECTROMETRY 3.3.1 Operating Principle... 

Infrared and ultraviolet probes for surface analysis are then considered.The applications of IR spectroscopy and Raman microscopy are discussed, and a brief account is also given of laser-microprobe mass spectrometry (LAMMA). 

Van Vaeck, L. Struyf, H. Van Roy, W. Adams, F. Organic and inorganic analysis with laser microprobe mass spectrometry. Mass Spectrom Rev. 1994,13,189-208. 

Hara, K., T. Kikuchi, K. Furuya, M. Hayashi, and Y. Fujii, Characterization of Antarctic Aerosol Particles Using Laser Microprobe Mass Spectrometry, Environ. Sci, Technol., 30, 385-391 (1996). 

Today the population is becoming increasingly exposed to ultrafine particles (< 20 nm, e.g., Aerosil, 2) in bodycare and household products. Ion microscopy studies revealed that such particles can, for example, penetrate the horny layer of the skin and can result in unexpected interactions. SIMS and Fourier transform laser microprobe mass spectrometry (FT LMMS) have been applied to study 2 stimulated interaction in thin layers of dermatological gels as a result of UV irradiation.175 For future studies of distribution of ultrafine particles LA-ICP-MS will be employed. 

Simons, D. S. Laser microprobe mass spectrometry, in Springer Series in Chemical Physics 36 (eds. Benninghoven, A.), et al., p. 158, Berlin, Heidelberg, New York, Tokyo, Springer 1984... 

Very few of these studies were directed at elemental analysis. They concentrated on analysis of molecular ions and on study of the structure and reactivity of cluster ions. Another area of investigation, laser microprobe mass spectrometry using FT-ICR mass analysis [84], has most often been concerned with organic impurities on and in materials. However, it can be used to detect elemental ions produced by the laser desorption process. 

Among the other soft ionization techniques is laser microprobe mass spectrometry (LAMMA) in which a laser pulse is used to vaporize a small amount of sample, as discussed in a 1982 review (108). Of interest to us is the application to the study of some cobalamins (109). (M + H) and (M - H) ions were observed in the positive and negative ion modes, respectively. However, there were few other high-mass fragments that could be used to impart structural information. 

Characterization thus involves analytical electron microscopy, ordinary microprobe analysis or other techniques for localizing elements or chemical compounds (Scanning Auger Spectroscopy, Raman Microprobe, Laser Microprobe Mass Spectrometry). It also requires, in most cases, some physical separation of the catalyst for separate analysis (e.g., near surface parts and center of pellets, by peeling or progressive abrasion pellets present at various heights in the catalyst bed, etc.). 

Hara K., Kikuchi T., Furuya K., Hayaffii M., and Fujii Y. (1996) Characterization of Antarctic aerosol particles using laser microprobe mass spectrometry. Environ. Sci. Technol. 30, 385-391. 

F. and Natusch D. F. S. (1982) Laser microprobe mass spectrometry I basic principles and performance characteristics, Anal Chem 54 26A-41A. 

Microprobe techniques, and their detection limits (given in mgkg ), that have been applied to Al localization include energy dispersive (electron probe) X-ray microanalysis (20), wavelength-dispersive X-ray microanalysis, electron energy loss spectrometry (500), proton probe nuclear microscopy (10), resonance ionization mass spectrometry (3), secondary ion mass spectrometry (1), laser microprobe mass spectrometry (1) and micropartide-induced X-ray emission (Yokel 2000). 

Two atomic mass s-pcccronieiric methods are often used to determine the elemental composition of solid surfaces secondary-ion mass spectrometry and laser microprobe mass spectrometry. These techniques arc-discussed in detail in Sections 21D-1 and 21D-.1. 

These workers also investigated eight industrially important high-mass polymers by laser microprobe FTICR. These polymers included PEG 8000, poly(phenylene sulfide) (MW 1.0 x 10 ), poly(vinyl acetate) (MW 6.4 x 10 ), poly(styrene) (MW 2.5 x 10 ), PMMA (MW 4.6 x 10 ), poly(vinyl chloride) (3.7 x 10 ), poly(acrylonitrile) (MW 2.3 x 10 ), and poly(dimethylsiloxane) (MW 4.4 x 10 ). Brenna and Creasy posed the question of whether broadband UV laser microprobe FTICR could be used to identify these polymers, and they also wanted to compare spectra with the more widely used TOF laser microprobe mass spectrometry (LAMMA). Results include the observation of odd-mass ions, carbon clustering (Figure 9.4), stable subunit condensation,... 

Optical microscopy (OM), polarized light microscopy (PLM), phase contrast microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM) are the methods normally used for identification and quantification of the trace amounts of asbestos fibers that are encountered in the environment and lung tissue. Energy-dispersive X-ray spectrometry (EDXS) is used in both SEM and TEM for chemical analysis of individual particles, while selected-area electron diffraction (SAED) pattern analysis in TEM can provide details of the cell unit of individual particles of mass down to 10 g. It helps to differentiate between antigorite and chrysotile. Secondary ion mass spectrometry, laser microprobe mass spectrometry (EMMS), electron probe X-ray microanalysis (EPXMA), and X-ray photoelectron spectroscopy (XPS) are also analytical techniques used for asbestos chemical characterization. 

Figure 2 Rationalization of the detected ions using the Dl model in LMMS by the effects of the (A) energy gradient created along the surface, (B) the pressure gradient in the selvedge, and (C) the time domain of ion formation and mass analysis. (Adapted from Van Vaeck L, Struyf H, Van Roy W, and Adams F (1994) Organic and inorganic analysis with laser microprobe mass spectrometry. Part I instrumentation and methodology. Mass Spectrometry Reviews 13 189-208 Wiley.)...

Hgure 3 Scheme for molecular speciation of inorganic compounds using FT-LMMS. (Reprinted with permission from Struyf H, Van Vaeck L, Poels K, and Van Grieken R (1998) Fourier transform laser microprobe mass spectrometry for the molecular identification of inorganic compounds. Journal of the American Society for Mass Spectrometry 9 482-497 Elsevier.)... 

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