Laser Microprobe Mass Spectrometry for Spatially Resolved Organic Analysis

Within the last twenty years, lasers were used for sample ionization in mass spectrometry by coupling nearly any available type of laser to the different kinds of available mass analyzers. There is a broad area of applications of the so-called laser ionization/desorption mass spectrometry (LIMS, LDMS) in a large variety of fields, such as geology, mineralogy, material research, general chemistry and biochemistry ranging from determination of bulk elemental composition to molecular weight determination of biological macromolecules. By combining an UV-microscope with a short-pulse UV-laser (for sample observation and focused irradiation of selected sample areas within μm-resolution) and a time-of-flight mass spectrometer, the technique of laser microprobe mass spectrometry was established (LAMMA-, LIMAtechnique). Also laser microprobe mass spectrometry was applied in very different fields. Most of the work dealt with the determination of element distributions within biological samples, usually prepared as thin sections and examined with a transmission geometry, i.e. by perforating the compartment of sample to be analyzed with a high intensity laser beam.