Abstract: An analysis of type, state or other distinguishing features of individual cells from body fluids, smears or tissues includes the steps of depositing the cells, with a minimum possible overlap, on a mass spectrometric sample support, determining the coordinates of the cells, coating the sample support with a layer of small crystals of a matrix substance, positioning the cells, inside a mass spectrometer, according to their known coordinates with a movement device into the position of the laser focus, acquiring mass spectra of the individual cells with ionization of the cell components by matrix assisted laser desorption, and using the mass spectra for an analysis of type, state or other distinguishing features of the cells.

Abstract: The invention relates to a method and a device for optimization of electric fields in measurement cells of Fourier transform ion cyclotron resonance mass spectrometers. The invention is based on the rationale that asymmetric electric fields with uniformly or non-uniformly perturbed field axes can appear in ion cyclotron resonance cells and therefore the axis of the magnetron orbit can become radially displaced. Shifted magnetron orbits negatively affect the cyclotron excitation, deteriorate the FT-ICR signal, increase the intensity of an even-numbered harmonics peak, lead to stronger side bands of the FT-ICR signal, and in extreme cases, cause loss of ions. The present invention helps in probing the shift of the magnetron motion, detecting parameters indicative of the offset of the electric field axis and/or correcting it by trimming it back to the geometric axis of the cell.

Abstract: In an ion mobility spectrometer in which a gas flows through a gas-tight tube with a radially quadrupolar RF field therein and blows ions against a DC electric field barrier, a mobility scan with a mobility scale that is linear in time is obtained by holding the height of the DC electric field barrier constant while changing the pressure and temperature conditions of the flowing gas. Alternatively, the mobility scan is performed by holding the pressure and temperature conditions of the flowing gas constant and reducing the height of the DC electric field barrier non-linearly with respect to time.

Abstract: The invention relates to a method and a device for optimization of electric fields in measurement cells of Fourier transform ion cyclotron resonance mass spectrometers. The invention is based on the rationale that asymmetric electric fields with uniformly or non-uniformly perturbed field axes can appear in ion cyclotron resonance cells and therefore the axis of the magnetron orbit can become radially displaced. Shifted magnetron orbits negatively affect the cyclotron excitation, deteriorate the FT-ICR signal, increase the intensity of an even-numbered harmonics peak, lead to stronger side bands of the FT-ICR signal, and in extreme cases, cause loss of ions. The present invention helps in probing the shift of the magnetron motion, detecting parameters indicative of the offset of the electric field axis and/or correcting it by trimming it back to the geometric axis of the cell.

Abstract: The invention relates to a method for the detection of incorrect deposition on a MALDI sample support with several separate sample sites, where after the preparation on the sample support, an area located between two sample sites is sampled with a desorption laser, and a signal of an ion detector in a mass spectrometer is acquired in temporal relation to the sampling. The signal is examined for the presence of a signal which indicates incorrect deposition. An advantage of the method is particularly that it can be carried out using a MALDI ion source and a connected mass analyzer, and that it requires little procedural effort.

Abstract: An electrostatic Kingdon ion trap in which ions can oscillate harmonically in the longitudinal direction, decoupled from their motions in the transverse direction is formed from at least three inner electrodes located inside a hollow outer housing electrode. The inner surface of the housing electrode and the outer surfaces of the inner electrodes are formed so that when a potential is applied between the housing and the inner electrodes, the potential distribution inside the housing contains not only a term for a harmonic potential well in the axial direction, but also a term for the potential distribution in the radial direction, that contains, independent of the axial coordinate, the equations for a family of Cassini curves of at least the third order.

Abstract: Devices and methods for the acquisition of mass spectra with very high mass resolution in ion cyclotron resonance mass spectrometers include cylindrical ICR measuring cells with special electrode geometries to generate harmonic trapping potentials for orbiting ions. The sheath of the cylindrical cell is divided by longitudinal gaps into a multitude of sheath electrodes, which either have to carry layers with resistance profiles able to generate parabolic voltage profiles along the sheath electrodes, or which form sheath electrodes of varying width by parabolic gaps. Orbiting ions of a given mass m/z oscillate harmonically in an axial direction with the same frequency, independent of the radius of their orbit and their oscillation amplitude. Ideally, the cylinders are closed by endcaps with rotationally hyperbolic form, divided into partial electrodes. The ions are excited by dipolar excitation fields. The orbiting ion clouds are kept together for much longer periods than was possible hitherto.

Abstract: In an ion cyclotron resonance cell, which is enclosed at its ends by electrode structure elements with DC voltages of alternating polarity, longitudinal electrodes are divided so that the ICR measurement cell between the electrode structure elements consists of at least three sections. An excitation of ion cyclotron motions can be performed by applying additional trapping voltages to longitudinal electrodes located closest to the electrode structure elements and introducing ions into the center set of longitudinal electrodes. The ions are then excited into cyclotron orbits by applying radiofrequency excitation pulses to at least two rows of longitudinal electrodes to produce orbiting ion clouds. Subsequently, the additional trapping voltages are removed and an ion-attracting DC voltage is superimposed on the DC voltages. Ions excited to circular orbits can be detected using detection electrodes in the outer ICR cell sections.

Abstract: Microorganisms, particularly bacteria, are identified and characterized on the basis of a mass spectrometric measurement of their protein profiles with ionization by matrix-assisted laser desorption. In order to measure the microbial resistance to antibiotics, the protein profiles of microorganisms are measured after cultivation for a short time duration in nutrient media containing the antibiotics.

Abstract: In an ion cyclotron resonance cell, which is enclosed at its ends by electrode structure elements with DC voltages of alternating polarity, longitudinal electrodes are divided so that the ICR measurement cell between the electrode structure elements consists of at least three sections. An excitation of ion cyclotron motions can be performed by applying additional trapping voltages to longitudinal electrodes located closest to the electrode structure elements and introducing ions into the center set of longitudinal electrodes. The ions are then excited into cyclotron orbits by applying radiofrequency excitation pulses to at least two rows of longitudinal electrodes to produce orbiting ion clouds. Subsequently, the additional trapping voltages are removed and an ion-attracting DC voltage is superimposed on the DC voltages. Ions excited to circular orbits can be detected using detection electrodes in the outer ICR cell sections.

Abstract: In an ion cyclotron resonance mass spectrometer ions are excited into cyclotron orbits by an alternating current excitation signal having a nonlinear function of the excitation frequency vs. time in a “chirp.” Such an excitation signal produces transients which have no pronounced beats, even if mixtures of many ion species, all having the same mass differences, are present. The dynamic measuring range for the image currents can thus be better utilized. In particular, sum spectra of specified quality can be generated from a significantly smaller number of individual transients, and thus in a significantly shorter measuring time.

Abstract: A device for use in a mass spectrometer allows an ion-optical assembly to be removed, cleaned and reinserted with relatively high positioning accuracy. In particular, the device obviates the need for complex adjustments requiring special knowledge after the reinsertion. The objective is achieved by an arrangement comprising a receptacle and a mount for a removable ion-optical assembly in a mass spectrometer. Favorable implementations provide a mount and a receptacle with three pairs of complementary support elements, the three support elements on the receptacle form a support plane, and, when the mount is inserted into the receptacle, at least two pairs of support elements are engaged and the mount is aligned with respect to the support plane with the aid of the third pair of support elements.

Abstract: In an ion mobility spectrometer in which a gas pushes ions along a spectrometer axis against and over an electrical field barrier, the electric field barrier is generated with a plateau of slightly increasing height along the axis of the spectrometer. Alternately, the electric filed barrier may have a plateau with constant height, but the gas flow decreases in velocity along the axis of the spectrometer in the vicinity of the plateau.

Abstract: Radical anions for use in the fragmentation of positively charged biopolymer ions by means of electron transfer are produced from substances previously unknown for use as ETD production substances. The inventive substances produce radical anions that lead to electron transfer dissociations with a high yield of fragment ions. The substances have high volatility that allows them to be kept in unheated containers outside the vacuum system and transported into the vacuum system to an in vacuum electron attachment ion source via unheated lines and low molecular weights that allow the measurement of even very light fragment ions. In one embodiment, a suitable substance is 1-3-5-7-cyclooctatetraene.

Abstract: Spatially resolved tissue states (status image) are determined from spectrally resolved mass spectra of a tissue section by (a) acquiring a plurality of spatially resolved mass spectra of the tissue section, (b) generating at least two mass images from the spatially resolved mass spectra, (c) smoothing the mass images using an edge-preserving smoothing algorithm and (d) calculating a status image from the smoothed mass images by means of a classification algorithm derived from mathematical statistics.

Abstract: An improved deposition aid for manual sample preparation, particularly on flat MALDI sample supports, comprises a holder for a sample support with several sample sites, which is adapted to standardized sample supports for ionization with matrix-assisted laser desorption and a device which projects a two-dimensional optical image, or a suitable sequence of images, onto the sample sites. The image, or sequence of images, is constructed such that a selected sample site or group of selected sample sites is highlighted in a way which can be perceived by the human eye, at least with respect to neighboring, not-selected sample sites. The deposition aid also includes an interface for confirming the manual deposition and/or a device for the automatic detection of a manual deposition process; and a guidance system which selects a sample site or group of sample sites, and controls the device accordingly.

Abstract: A simplified sample preparation on a sample support for ionization with laser desorption (MALDI or LDCI, for example) includes depositing an analyte material onto a deposition site, providing a sample site which is intended as the substrate for a matrix crystal layer at a distance from the deposition site, and establishing a liquid communication between the deposition site and the sample site. A device for the preparation of samples for ionization with matrix-assisted laser desorption, and a sample support for use with the inventive method are also disclosed.

Abstract: The invention relates to a method to assist with the manual preparation of a sample support for ionization with matrix-assisted laser desorption where a sample support with sample sites is provided, a selected sample site is highlighted in a way which can be perceived by the human eye at least with respect to neighboring, not selected sample sites, a sample is manually deposited on the selected and highlighted sample site, and the deposition state of at least the selected and highlighted sample site is determined. The method enables the sample preparation and sample analysis to be made more efficient and more certain.

Abstract: A calibration function for time-of-flight mass spectrometers that converts ion times of flight into mass to charge ratios, takes into account not only the time of flight of a specific ionic species, but also the ion signal intensity of that ionic species. Use of the conversion function reduces nonsystematic deviations of the calculated mass values from the true mass values previously experienced in time of flight mass spectrometers.

Abstract: Microorganisms, particularly bacteria, are identified and characterized on the basis of a mass spectrometric measurement of their protein profiles with ionization by matrix-assisted laser desorption. In order to measure the microbial resistance to antibiotics, the protein profiles of microorganisms are measured after cultivation for a short time duration in nutrient media containing the antibiotics.