Images of the masses: Two‐dimensional molecular imaging of intact rat brain tissue under ambient conditions was achieved by using the mass spectrometric technique of desorption electrospray ionization (DESI). The distributions of specific lipids, such as sulfatide 24:1, reveal distinctive subanatomical features of the rat brain (cc=corpus callosum; aca=anterior part of anterior commissure) with spatial resolution of less than 500 μm.

A shoebox-sized, 10-kg, handheld mass spectrometer, Mini 10, based on a rectilinear ion trap mass analyzer has been designed, built, and characterized. This instrument has evolved from a decade-long experimental and simulation program in mass spectrometer miniaturization. The rectilinear ion trap has a simplified geometry and high trapping capacity, and when used with a miniature and ruggedized pumping system, it allows chemical analysis while the instrument is being carried. Compact electronics, including an air core RF drive coil, were developed to control the instrument and to record mass spectra. The instrument runs on battery power, consuming less than 70 W, similar to a laptop computer. Wired and wireless networking capabilities are implemented. The instrument gives unit resolution and a mass range of over m/z 500. Tandem mass spectrometry capabilities are implemented using collision-induced dissociation, and they are used to provide confirmation of chemical structure during in situ analysis. Continuous monitoring of air and solution samples is demonstrated, and a limit of detection of 50 ppb was obtained for toluene vapor in air and for an aqueous naphthalene solution using membrane sample introduction.

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Proteome coverage and peptide identification rates have historically advanced in line with improvements to the detection limits and acquisition rate of the mass spectrometer. For a linear ion trap/Orbitrap hybrid, the acquisition rate has been limited primarily by the duration of the ion accumulation and analysis steps. It is shown here that the spectral acquisition rate can be significantly improved through extensive parallelization of the acquisition process using a novel mass spectrometer incorporating quadrupole, Orbitrap, and linear trap analyzers. Further, these improvements to the acquisition rate continue to enhance proteome coverage and general experimental throughput.

Bilder nach Masse: Die zweidimensionale molekulare Bildgebung von intaktem Rattenhirngewebe unter Umgebungsbedingungen gelingt mithilfe von Desorptionselektrosprayionisations(DESI)‐Massenspektrometrie. Die Verteilung einzelner Lipide, wie Sulfatid 24:1, deckt unverkennbare subanatomische Merkmale des Rattenhirns mit einer Auflösung unter 500 μm auf (cc=Corpus Callosum; aca=vorderer Teil der Commissura anterior).