Abstract: The invention relates to the use of a time-of-flight mass spectrometer to analyze substance molecules which are ionized by laser desorption, particularly by matrix-assisted laser desorption (MALDI). In detail it relates to the process for improving mass resolution by the known method of delayed acceleration of the ions in the space in front of the sample support plate. The invention consists of switching the potential of an intermediate electrode which is located at a short distance in front of the sample support plate, instead of switching the potential of the sample support plate itself.

Abstract: A method is provided for analyzing analyte ions in a liquid using a spectrometer incorporating an ion trap, using a capillary nozzle adjacent an inlet aperture for the ion trap. The liquid is electrosprayed from the capillary nozzle by generating an electric field at the nozzle to ionise the said analyte and produce a beam of charged spray particles, and the beam of charged particles is injected into the ion trap through the inlet aperture. The pressure within the capillary is such that flow of the liquid through the capillary occurs only in the presence of the said electric field, and flow of ions into the ion trap is controlled by varying the electric field.

Abstract: The invention relates to the mass spectrometric analysis of separated substance samples on so-called 2-D-gel electrophoresis plates, used particularly for protein determination, with ionization of the substance samples by MALDI. The molecules of the substance samples are transferred to a thin, lacquer-like smooth matrix layer which should preferably be applied to a metal sample support. Transfer takes place directly or indirectly, for example via a polyvinylidene difluoride membrane an an intermediate carrier, by electrophoretic transport of the molecules to the matrix surface. Before transfer, the proteins may be subjected to enzymatic cutting of their amino acid chains.

Abstract: The invention relates to methods and devices for the reflection of positively and negatively charged particles of moderate kinetic energies at surfaces of any form. The invention consists in the production of a virtual or real surface for reflecting charged particles by creation of strongly inhomogenous high frequency fields of low penetration range into the space above the surface. The inhomogenous electric field is produced by supply of a high frequency voltage to a narrow grid pattern forming the surface and consisting of electrically conducting electrodes, isolated from each other. The electrode elements of the pattern are regularly repeated in at least one direction within the surface. The phases of the high frequency voltage are connected alternately to subsequent grid elements. The invention can be used to build new types of ion storage devices and ion guides for the transport of ions in moderate and high vacuum. New types of mass filters can be produced by this invention.

Abstract: The invention relates to a method of automatically controlling the space charge in ion traps when they are used as a mass spectrometer. If ionization conditions remain the same, space charge is proportional to the measured concentration of a substance; if there are rapid changes in substance concentrations, as can be found in coupling with gas chromatography for example, the space charge must be controlled to obtain spectra of consistent quality. The invention is based on the possibility of performing rapid consecutive scans and consists in utilizing the integrated ion currents of consecutive spectra to forecast by calculation the value of the ion generation rate at the time of the ionization phase for the next scan. Calculation may be based on linear, quadratic or cubic extrapolation but also on assumptions regarding the function of change of the concentration, and an adaptation of the function parameters.

Abstract: The invention relates to virtual impactors with slits. Virtual impactors serve to enrich aerosol particles of certain orders of magnitude from gases, particularly from the ambient air, for the purpose of examining such particles. For very high degrees of enrichment to many hundreds of times the initial concentration very effective multistage virtual impactors have been developed with hundreds of nozzles but the latter are difficult to manufacture and clean. In principle the individual nozzles can be replaced by slits which are easier to manufacture. Since the ends of the slits cause considerable stability problems for the stream of gas the invention proposes using circular slits without ends.

Abstract: A method of fragmenting ions in conventional nonlinear ion traps using collisions of ions with molecules of a collison gas with excitation of the secular oscillations of the ions. A mixture of frequencies for resonant excitation, with a frequency limit which prevents the ions from being excited beyond the maximum oscillation amplitude between the end caps.

Abstract: A method is disclosed for chemical ionization of the molecules of an analysis gas or analysis gas mixture or for studying ion-molecule reactions in ion traps. Specifically, by superposing a quadrupole field with a dipolar introduced frequency mixture in which there are accurately selected frequency gaps in the ionization phase of the analysis, the only ions which are stored are those which are on the selected reaction path of the reactant gas ions for making the proper reactant ions for the desired ion-molecule reaction. All the other ions are eliminated from storage by excitation of their secular oscillations. In a second phase, by switching off the dipolar introduced frequency mixture, all the ions can be stored in a wide range of mass-to-charge ratios, and therefore also the product ions of the desired ion-molecule reactions of the analysis gas. In a third phase the spectrum of the product ions is scanned.

Abstract: The invention relates to a device and a method for mass-spectrometric analysis of substance samples which have been separated by capillary electrophoresis, particularly proteins, proteoglycanes or other protein conjugates, with ionization of the substance samples by a particularly substance-saving form of electrospraying. A method of "microspraying" is used which permits a flow of spray liquid of only several tens of nanoliters per minute in stable spray operation. The invention consists in a loose coupling of the spray capillary to the electrophoresis capillary in a liquid environment.

Abstract: A method of electrospraying and thereby ionizing an analyte present in a liquid, using a capillary nozzle, in which an electric field is generated at the nozzle to ionise the analyte and produce a divergent beam of charged spray particles. The pressure within the capillary is such that flow of the liquid through the capillary occurs only in the presence of the electric field.

Abstract: An ion trap is provided in which higher multipole field fractions can be switched on and off and, in addition, can be electrically tuned. Specifically, the electrodes of an ideally shaped ion trap are divided into rotationally symmetrical component electrodes positioned facing the interior of the ion trap on a hyperboloidal surface with rotationally symmetry.

Abstract: The invention relates to an improved method and an apparatus for the mass-sequential ejection of ions from an RF quadrupole ion trap by electrical alternating fields which are generated in addition to the quadrupolar RF storage field and with different frequencies to it. In contrast to the already known ejection by a pure dipole field, the ions are here essentially ejected by a quadrupole field. The ions leave the ion trap through a perforated end cap and can be detected outside it with conventional means. A weak dipole field undertakes only excitation of the secular oscillation at the center, the amplitude increasing in linear manner in the stationary case. The more intense quadrupole field undertakes further widening of the oscillations with exponential growth in amplitudes. The dipole field is generated by an alternating voltage between the two end caps, while the quadrupole field is generated by an alternating voltage between the end caps on the one hand and the ring electrode on the other.

Abstract: A planar gating grid for an IMS spectrometer is constructed with two sets of comb-like grid elements. Each set is connected to an electrode and the sets are interdigitated to form the grid. Mechanical stability is provided by attaching the grid elements to an insulating support member. The gating grid is produced from a thin metal foil by cutting or etching the foil to produce a rigid grid structure where all of the elements are connected to both electrodes and the electrodes are separated by a stretcher member. After the rigid grid structure is affixed to the insulating support member, the grid elements are selectively severed from one of the two electrodes to form the interdigitated grid.

Abstract: The invention relates to a method and a device for detecting very large molecular ions in a time-of-flight mass spectrometer, in which the molecules to be detected first fall with high energy (>8 keV) onto a conversion dynode and are then converted into an electronic signal in a sequence of stages. The rnolecules to be detected are at least partly converted into small (<200 u) positive and negative secondary ions on the conversion dynode. The secondary ions formed are accelerated, optionally positive or negative, onto a microchannel plate, where they are converted into electrons. The electrons are amplified in the microchannel plate and then accelerated onto a scintillator. The electron signal is converted into a light signal in the scintillator, being further amplified. A connecting fiber-optic light guide supplies the photons to a photomultiplier, in which they are converted in customary manner into a signal which can be evaluated electronically.

Abstract: A method and a device for the mass selective excitation of the secular oscillations of selected ion types in an RF quadrupole ion trap, including the simultaneous excitation of more than one ion type, is disclosed. The secular oscillation frequency is excited by resonances with specific frequencies of the frequency bands of the additional alternating fields, the frequency bands being generated digitally at a basic pulse rate .OMEGA.. Interfering frequency side bands .OMEGA.-.omega., .OMEGA.+.omega., 2.OMEGA.-.omega., 2.OMEGA.+.omega., etc. arise, however, for each frequency .omega. within the frequency bands. These side bands can excite and eliminate other ions, which are not to be eliminated, in an undesired manner. The invention comprises forming the side bands in such a way that they only excite the selected ions.

Abstract: The invention concerns a sampling device for a mobile analysis unit, in particular a mass spectrometer (13), used for the purpose of monitoring chemical substances on ground surfaces. It possesses at least one sampling wheel which revolves around an axle and which consists of a silicone tire (5) for picking up molecules of substances to be monitored and a wheel rim (6) upon which the silicone tire is fitted. The wheel rim (6) is made of metal such as stainless steel or aluminum. This means that on the one hand contamination of the silicone tire (5) by vapors from the wheel rims (6), in the course of long-term storage of the sampling wheels in airtight, closed storage containers, is prevented. On the other hand, the invention facilitates an advantageous construction of the wheel rim (6), involving the mounting of two, thin-walled rim halves (9) with rivet holes.

Abstract: An ultra-high vacuum valve for the admission of substance mixtures into an analytical measuring instrument limits the flow path of the substances to as small a flow chamber as possible with controllable chamber wall adsorption properties. The elastic wall sections necessary for movement of the valve piston are located in a mechanical chamber separated from the flow chamber by a wall. The mechanical chamber is evacuated by means of a separate vacuum duct and a seal is used to seal the valve piston where it passes through the wall.

Abstract: The measuring process for generating mass spectra using a sequentially-scanned quadrupole ion trap mass spectrometer, is improved by controlling the measurement of the ion packages ejected from the ion trap so that measurement takes place starting at the anticipated exit times of the ion packages and measurement continues only as far as possible for a time duration corresponding to the length of the ion packages. Measuring only during ion package ejection enables a measurement for the total number of ejected ions having a selected mass to be obtained by means of digital addition of the individual package measurements. Subsequent processing of the data can be carried out with practically only the fluctuations of normal ion counting statistics.

Abstract: Heavy-weight, fast-moving molecular ions are slowed down in a light-weight collision gas to very low velocities and small distributions of velocity before their mass-spectrometric analysis. The velocity reduction of the ions which occurs in the collision gas reduces both ion energy and phase space. In accordance with one embodiment, in order to minimize fragmentation of large molecular ions, an ultrasonic gas jet traveling in the same direction as the ions is used for slowing down the ions. In accordance with another embodiment, the ions are examined in storage mass spectrometers such as ICR spectrometers or ion traps.

Abstract: An improvement of a fast scanning method in an ion trap mass spectrometer comprises setting the frequency and phase relationships between the ion trap storage frequency and the ion trap excitation frequency in such a way that the ions of consecutive masses each gain precisely the same "phase rhythm" or "phase sequence". The phase rhythm, or the historical succession of phase positions up to ion ejection, is optimally set in accordance with nonlinear resonance conditions used to cause ion ejection. The excitation voltage frequency is set to a value somewhat smaller that an integral fraction of the storage voltage frequency and the scan profile is set based on the excitation frequency so that the same time is required for ions of each mass to be ejected and so that precisely an integer number of cycles of the excitation frequency is used per mass.