LAMMA 1000, analyses with

In Laser Ionization Mass Spectrometry (LIMS, also LAMMA, LAMMS, and LIMA), a vacuum-compatible solid sample is irradiated with short pulses ("10 ns) of ultraviolet laser light. The laser pulse vaporizes a microvolume of material, and a fraction of the vaporized species are ionized and accelerated into a time-of-flight mass spectrometer which measures the signal intensity of the mass-separated ions. The instrument acquires a complete mass spectrum, typically covering the range 0— 250 atomic mass units (amu), with each laser pulse. A survey analysis of the material is performed in this way. The relative intensities of the signals can be converted to concentrations with the use of appropriate standards, and quantitative or semi-quantitative analyses are possible with the use of such standards. 

The technique is referred to by several acronyms including LAMMA (Laser Microprobe Mass Analysis), LIMA (Laser Ionisation Mass Analysis), and LIMS (Laser Ionisation Mass Spectrometry). It provides a sensitive elemental and/or molecular detection capability which can be used for materials such as semiconductor devices, integrated optical components, alloys, ceramic composites as well as biological materials. The unique microanalytical capabilities that the technique provides in comparison with SIMS, AES and EPMA are that it provides a rapid, sensitive, elemental survey microanalysis, that it is able to analyse electrically insulating materials and that it has the potential for providing molecular or chemical bonding information from the analytical volume. 

The origin of lead present in individual calcite particles could be ascribed by the LAMMA (laser microprobe mass analysis) technique. At low laser irradiances, the desorption mode, information is gathered on metallic species adsorbed on the surface of the particle. At high irradiances the particle is evaporated, revealing the components that coprecipitated with calcite111. 

Laser microprobe mass analyzers permit mass spectrometric analysis of very small volumes (0.01-1 pm3) of thin Sections. The method is based on laser induced ion production from a microvolume and analysis of the evaporated ions in a time-of-flight mass-spectrometer. The technique allows detection of all elements and isotopes with a sensitivity approaching the ppm range and an extremely low limit of detection 10 15 to 10-20 g. Transmission type instruments such as the LAMMA 500 are designed for the analysis of particles of 3 pm in diam. The lateral resolution is about 0.5-1 pm. Because the area to be analyzed is selected by an optical microscope, distribution of chemical constituents can be precisely correlated with morphologic structures (Hillenkamp et al., 1982 39), Simons, 198440), Kaufmann, 1984)41 >. 

Thin Sections or pieces of the rock about 1 mm in size or less can be also analyzed with this instrument at glancing incident irradiation, if the site to be analyzed is close to the surface of the section or the edge of a fraction. However in this mode of operation, mass resolution is severely reduced. Nevertheless ions can be identified because of their low mass numbers and the very low background in the spectra, by known cluster patterns or by comparison with reference spectra obtained with reduced laser irradiation. The spectra have shown to be highly reproducible. For more precise bulk. sample analysis, other instruments such as the LAMMA 1000 are more suited. Their lateral resolution is 1-3 pm in diameter and the depth of analysis is typically 0.1 pm. 

LAMMA has been utilized for the analysis of aluminum in brain tissue affected with Alzheimer s disease (Lovell et al. 1993). This new analytical technique of nuclear microscopy can simultaneously image and analyze features in unstained and untreated tissue sections, and therefore avoids contamination problems associated with tissue prepared using conventional chemical techniques. LAMMA was used in a study... 

For example, microprobe analysis of complex samples (laser microprobe mass analysis LAMMA) was performed by using a setup with no expansion chamber and by focusing the laser beam on a small area on the surface of the sample. Although coal and shale samples were successfully analyzed using LAMMA [52], the nature of the bonding in these types of materials cannot be evaluated because it is not clear if a certain compound is the result of desorption or of pyrolysis. More successfully analyzed were the inorganic components of such composite materials where the thermal decomposition was not a concern. 

Analyses With The LAMMA 1000. As mentioned earlier, the degree of fragmentation of a molecule controls the amount of useful Information to lead to a molecular analysis. I mentioned two examples of excessive fragmentation. Therefore, precise control and measurement of very low laser power applied to the spectrum Is essential. Frank Anderson, analytical chemist of my laboratory, carried over a concept from his Transmission Electron... 

Schmidt. P.F. (1984). Localization of trace elements with the laser microprobe mass analyzer (LAMMA), Trace Elements in Medicine, 1,13-20 Sherwood. R.A., Rocks, B.F., and Riley, C. (1984). The use of flow-injection analysis (FIA) with atomic absorption detection for the determination of clinically relevant elements. Paper presented at 2nd BNAAS Symposium, Leeds, July 1984 Triebig, G., and Schaller, K.H. (1984). Copper, in Alessio, L, Berlin, A., Boni, M., Roi, R., Biological indicators for the assessment of human exposure to industrial chemicals, p. 57-62, EUR 8903 EN, Commission of the European Communities Van der Vyner, F.L, Verbreuken, A.H., Van Grieken, R.E., and DeBroe, M.E. (1985) Laser microprobe mass analysis A tool for evaluating histochemical staining of trace elements, Clin. Chem., 31. 351... 

LAMMA, or LAMMS, or LMMS (laser microprobe mass analysis or spectroscopy), is based on laser ablation. A high frequency laser beam scans the area of the sample in a minimum step size, time-of-flight mass spectra of each scan are evaluated with respect to several ion signals and transformed into two-dimensional distribution plots. 

Laser ionization The identification of unknown inclusions in a variety of matrices is very important in an industrial environment. One method used to analyze these unwanted small ( 1-50 pm diameter) inclusions is laser desorption/ionization mass analysis, also known as laser microprobe mass spectrometry and laser microprobe analysis. Trade names used are LIMA (laser ionization mass analyzer) and LAMMA (laser microprobe mass analysis). A variable-power laser is focused on to the inclusion. As discussed above, the desorption/ionization process is very sensitive to the power density of the laser at the sample surface. Firing the laser with an appropriate power setting generates ions containing information about the inclusion, which are then mass-analyzed using TOF-MS. 

Lasers have been used in mass spectrometry for many years. Trace elements in biological samples [90] can be determined by using laser microprobes (LAMMA, laser microprobe mass analyzer) or a combination of laser ablation with ICPMS. For the analysis of bulk materials, techniques such as resonance ionization mass spectrometry (RIMS) and laser ablation MS (LAMS) are employed for a review see [91]. 

Principles and Characteristics Laser microprobe mass spectrometry (LMMS, LAMMS), sometimes called laser probe microanalysis (LPA or LPMA) and often also referred to as laser microprobe mass analysis (LAMMA , Leybold Heraeus) [317] or laser ionisation mass analysis (LIMA , Cambridge Mass Spectrome-try/Kratos) [318], both being registered trademarks, is part of the wider laser ionisation mass spectrometry (LIMS) family. In the original laser microprobe analyser, emitted light was dispersed in a polychro-mator. Improved sensitivity may be obtained by secondary excitation of ablated species with an electric spark. In the mass spectrometric version of the laser microprobe, ions formed in the microplasma... 

A number of techniques are available, including laser microprobe mass analysis (LAMMA) and various microprobes, that are capable of determining within tissues or cell preparations the cellular and subcellular distribution of lead in situ. While these techniques generally require varying levels of sample preparation (e.g., tissue fixation, cell suspensions, etc.), they provide powerful tools for probing different cellular compartments and processes involving lead. Thus, the site-specific distribution of lead can be used to evaluate local toxicity, which can be correlated with pathological alterations in tissues. 

LAMM A. Laser microprobe mass analysis was specifically developed to complement other microanalytical techniques to determine intracellular distributions of physiological cations and toxic constituents in biological tissues. LAMMA is an analytical methodology capable of simultaneous multielement analysis of metals and their distribution on a cellular or subcellular scale, with a measurement sensitivity of 10" to 10" " g for most metals. LAMMA has received somewhat widespread use in the analysis of essential and toxic metals in tissues and cell preparations (Drueke 1980 Goebel et al. 1990 Schmidt and Barckhaus 1991 Schmidt et al. 1980, 1986 Vandeputte et al. 1985 Verbueken et al. 1984 Visser et al. 1984). The detection sensitivity of LAMMA for lead is 5 /rg/g, with a limit of detection of approximately 2 X 10" g (Schmidt and Barckhaus 1991). 

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