A new instrument and method is described for laterally resolved mass spectrometric surface analysis. Fields of application are in both the life sciences and the material sciences. The instrument provides for imaging of the distribution of selected sample components from natural and artificial surfaces. Samples are either analyzed by laser desorption ionization (LDI) time-of-flight mass spectrometry or, after preparation with a suitable matrix, by matrixassisted laser desorption ionization (MALDI) mass spectrometry. Areas of 100 ϫ 100 m are scanned with minimal increments of 0.25 m, and between 10,000 and 160,000 mass spectra are acquired per image within 3 to 50 min (scan rate up to 50 pixels per s). The effective lateral resolution is in the range of 0.6 to 1.5 m depending on sample properties, preparation methods and laser wavelength. Optical investigation of the same sample area by UV confocal scanning laser microscopy was found to be very attractive in combination with scanning MALDI mass analysis because pixel-identical images can be created with both techniques providing for a strong increase in analytical information. This article describes the method and instrumentation, including first applicational examples in elemental analysis, imaging of pine tree roots, and investigation of MALDI sample morphology in biomolecular analysis. (J Am Soc Mass Spectrom 2002, 13, 735-748)

The loss of anions takes place inside the mass spectrometer, generating the multiply charged ions needed for detection and calculation of the molecular weight. ["] Moleculqr mechanics were performed on Go -C3. The square-planar coordination environment of the Pd centers is well preserved. It is clear that after the second generation the structure of the dendrimer becomes quite entangled (Fig. 2). 5 nm Fig 2. Optimircd structures of G,, G ,We have shown that organometallic structures of nanometer dimensions can now be constructed in a very simple and controlled way. This method of controlled assembly provides a new and versatile tool for dendrimer synthesis. The method allows large variation in the metal in each generation, the coordinating ligands, and the structure of the nucleus. Received. December 29, 1995 [Z86901E] German version Arigeii . C/iern.

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