Structural Analysis of Organic Compounds by Laser Microprobe Mass Spectrometry (LAMMA)

The objective of this study was exploration of the potential, offered by the laser microprobe mass spectrometer (LAMMA), for the in situ localization of organic targets in embedded tissues by means of structurally relevant ions. A series of model systems was designed to evaluate stepwise the analytical problems involved. A preliminary screening pointed to the position of the target in comparison to the actual sample surface as a determining parameter. Refined simulations were carried out with sandwich samples, consisting of an epon carrier (thickness 1 micron), coated with microcrystalline targets and covered with a layer between 5 and 50 nm of different materials (epon, carbon, formvar). In addition to the stimulated conversion of molecular into fragment ions, the presence of a barrier leads to a drastic loss of sensitivity (20-50 x) and unacceptable degradation of the mass spectrometric quality (resolution, calibration).

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In-depth limitation of the Lamma 500 for thein situ localization of organic compounds in biological embedded tissue samples

Vaeck

Espen

Jacob

et al. 1988

Biol. Mass Spectrom.

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Structural characterization of drugs and oxygenated metabolites by laser microprobe mass spectrometry (LAMMA)

Vaeck

Espen

Gijbels

et al. 1988

Biol. Mass Spectrom.

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Laser microprobe mass analysis (LAMMA) was used for the structural characterization of polyfunctional drugs and their oxygenated metabolites, in particular the N-oxides. The spectra usually yield the molecular weight as well as intense fragments. The structural information is characteristically distributed between the positive and negative ions. To rationalize the unfamiliar fragmentation, tentative pathways are introduced. Key elements are the formation of odd-electron molecular (and fragment) ions, the correlation between cations and anions, as well as the three-dimensional representation of structures. The combination of mild desorption and abundant fragmentation makes LAMMA a valuable tool in the study of N-oxides.

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Enhanced silver cationization of polycyclic aromatic hydrocarbons containing bay regions in molecular secondary ion mass spectrometry

Hand

Winger

Cooks

1989

Biol. Mass Spectrom.

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The relative abundances of silver cationized molecules [Ag + m+ relative to molecular ions (M") in the secondary ion mass spectra of polycyclic aromatic hydrocarbons (PAHs) are directly related to the structures of the PAHs. Compounds containing a 'bay region', a concave area at the periphery of the molecule, give [Ag + MI+ : M+' abundance ratios which exceed 0.62, whereas this ratio is less than 0.18 for the molecules that lack this structural feature. This allows the recognition of PAHs containing bay regions and the distinction of certain isomeric PAHs, such as phenanthrene and anthracene. Other metals, including copper and nickel, show similar behavior.

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Structural Analysis of Organic Compounds by Laser Microprobe Mass Spectrometry (LAMMA)

Cited by 8 publications

References 50 publications

In-depth limitation of the Lamma 500 for thein situ localization of organic compounds in biological embedded tissue samples

In-depth limitation of the Lamma 500 for thein situ localization of organic compounds in biological embedded tissue samples

Structural characterization of drugs and oxygenated metabolites by laser microprobe mass spectrometry (LAMMA)

Enhanced silver cationization of polycyclic aromatic hydrocarbons containing bay regions in molecular secondary ion mass spectrometry

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