Abstract: An ion detector comprises an ion guide with electrodes arranged about a first axis; a positive ion detection device with an ion inlet at a first side of the ion output section offset from and at an angle to the first axis; and a negative ion detection device with an ion inlet at a second side opposite the first side, offset from and at an angle to the first axis. A negative voltage bias applied to the positive ion device accelerates positive ions toward the inlet along a path including a component along a second axis orthogonal to the first axis. A positive voltage bias applied to the negative ion detection device accelerates negative ions toward the inlet along a path that includes a component along the second axis orthogonal to the first axis in a direction generally opposite to the path of the positive ions.

Abstract: In a method controlling an ion detector, one or more ion input signals are received at the ion detector. A data point indicative of an intensity of at least one of the received ion input signals is acquired. Asynchronously with acquiring the data point, a drive voltage applied to the ion detector is regulated to operate the ion detector at a gain optimal for the intensity of at least one of the received ion input signals. An ion detector for implementing the method is also provided.

Abstract: An ion guide includes a plurality of curved electrodes and an ion deflecting device. The electrodes are arranged in parallel with each other and with a central curved axis, the curved central axis being co-extensive with an arc of a circular section having a radius of curvature, each electrode being radially spaced from the curved central axis, wherein the plurality of electrodes define a curved ion guide region arranged about the curved central axis and between opposing pairs of the electrodes. The ion deflecting device may include a device for applying a DC electric field to two or more of the electrodes in a radial direction. The ion deflecting device may include a pair of curved, parallel ion deflecting electrodes, which are in addition to curved electrodes utilized for applying an RF ion guiding field.

Abstract: In a method controlling an ion detector, one or more ion input signals are received at the ion detector. A data point indicative of an intensity of at least one of the received ion input signals is acquired. Asynchronously with acquiring the data point, a drive voltage applied to the ion detector is regulated to operate the ion detector at a gain optimal for the intensity of at least one of the received ion input signals. An ion detector for implementing the method is also provided.

Abstract: An ion detector comprises an ion guide with electrodes arranged about a first axis; a positive ion detection device with an ion inlet at a first side of the ion output section offset from and at an angle to the first axis; and a negative ion detection device with an ion inlet at a second side opposite the first side, offset from and at an angle to the first axis. A negative voltage bias applied to the positive ion device accelerates positive ions toward the inlet along a path including a component along a second axis orthogonal to the first axis. A positive voltage bias applied to the negative ion detection device accelerates negative ions toward the inlet along a path that includes a component along the second axis orthogonal to the first axis in a direction generally opposite to the path of the positive ions.

Abstract: Sample material ionized in a sample receiving chamber is flowed into a sample conduit. Drying gas may also flow into the sample conduit and may be heated. The pressure and length of the sample conduit may be provided according to the product 50 or greater Torr?cm. The sample conduit may include a turn. The sample conduit may lead to an ion extraction chamber at which a sampling orifice may lead to a mass spectrometer. The diameter of the sample conduit may be larger than the diameter of the sampling orifice. An electrical field may be applied in the ion extraction chamber to slow incoming ions. A voltage jump may be applied to the sample conduit.

Abstract: Sample material ionized in a sample receiving chamber is flowed into a sample conduit. Drying gas may also flow into the sample conduit and may be heated. The pressure and length of the sample conduit may be provided according to the product 50 or greater Torr-cm. The sample conduit may include a turn. The sample conduit may lead to an ion extraction chamber at which a sampling orifice may lead to a mass spectrometer. The diameter of the sample conduit may be larger than the diameter of the sampling orifice. An electrical field may be applied in the ion extraction chamber to slow incoming ions. A voltage jump may be applied to the sample conduit.

Abstract: In a method for inhibiting space charge-related effects in an ion source, an electron beam is directed into a chamber to produce ions from sample material in the chamber. A voltage pulse is applied to the chamber to perturb an electron space charge present in the chamber. The ion source may be an electron impact ionization (EI) apparatus. The ion source may operated in conjunction with a mass spectrometry system.

Abstract: In a method for inhibiting space charge-related effects in an ion source, an electron beam is directed into a chamber to produce ions from sample material in the chamber. A voltage pulse is applied to the chamber to perturb an electron space charge present in the chamber. The ion source may be an electron impact ionization (EI) apparatus. The ion source may operated in conjunction with a mass spectrometry system.

Abstract: In a method for optimizing an ion detector a control voltage, such as in a mass spectrometry system, an array of mass scan data is acquired. Based on the size of the largest peak in the array or part of the array, a determination is made as to whether the current detector gain should be changed to a new detector gain. If the current detector gain should be changed, the control voltage for the subsequent mass scan is adjusted to a new control voltage corresponding to the new detector gain. The data are scaled based on the current detector gain. In another method, a gain versus control voltage curve is generated for calibration. These methods may be implemented by hardware, software, analog or digital circuitry, and/or computer-readable or signal-bearing media.

Abstract: In a method for optimizing an ion detector a control voltage, such as in a mass spectrometry system, an array of mass scan data is acquired. Based on the size of the largest peak in the array or part of the array, a determination is made as to whether the current detector gain should be changed to a new detector gain. If the current detector gain should be changed, the control voltage for the subsequent mass scan is adjusted to a new control voltage corresponding to the new detector gain. The data are scaled based on the current detector gain. In another method, a gain versus control voltage curve is generated for calibration. These methods may be implemented by hardware, software, analog or digital circuitry, and/or computer-readable or signal-bearing media.

Abstract: The present invention involves a gel strip carrier module for a gel strip that reduces the handling of the gel strip and the hands-on-time during preparation of the gel strip for isoelectric focusing. The gel carrier module includes a gel strip chamber that serves as both a rehydration and focusing chamber, and allows the sample to be applied either throughout the entire gel or in a defined zone. The gel carrier module includes a pair of electrodes near opposite ends of the chamber that the gel strip rests on, gel side facing down. The gel carrier module includes a cover with hold-down blocks or pressure blocks to assure reliable, light contact between the gel and the electrodes during focusing. A rehydration buffer is added into the chamber, and the gel strip is gently placed in the chamber, gel side down, for rehydration.

Abstract: An ion collision cell for use in a mass spectrometer uses pre-collision and post-collision evacuation regions with a sealed collision region therebetween without the need for lens to separate the regions. A continuous rod design reduces mechanical cost and simplifies the electronic design. A longer collision cell allows lower pressure operation, and a curved configuration permits the exit of neutral particles. A square quadrapole cross-section allows a field free region in the center of the cell and minimizes ion node effects. In one embodiment, the ion collision cell includes first and second pole segments mounted on a first support plate with the pole segments having pole surfaces arranged at approximately 90° with respect to each other, and third and fourth pole segments mounted on a second support plate, the pole segments having pole surfaces arranged at approximately 90° with respect to each other.

Abstract: An electrical feedthrough connector to a low pressure (vacuum) chamber such as in a mass spectrometer comprises an epoxy body having at least two generally cylindrical portions with a step between the two generally cylindrical portions and with the portions mating with circular openings in the housing for the low pressure chamber. A step between the two cylindrical portions of the electrically insulating body mates with a step in the opening in the chamber housing with a gasket such as an o-ring placed between the steps to provide a pressure seal. A rigid printed circuit board with electrical components for an interconnect circuit is affixed to one end of the electrically insulating body with a flexible printed circuit connector extending from the rigid printed circuit board through the epoxy body to the low pressure chamber for interconnecting components within the chamber.

Abstract: The present invention involves a gel strip carrier module for a gel strip that reduces the handling of the gel strip and the hands-on-time during preparation of the gel strip for isoelectric focusing. The gel carrier module includes a gel strip chamber that serves as both a rehydration and focusing chamber, and allows the sample to be applied either throughout the entire gel or in a defined zone. The gel carrier module includes a pair of electrodes near opposite ends of the chamber that the gel strip rests on, gel side facing down. The gel carrier module includes a cover with hold-down blocks or pressure blocks to assure reliable, light contact between the gel and the electrodes during focusing. A rehydration buffer is added into the chamber, and the gel strip is gently placed in the chamber, gel side down, for rehydration.

Abstract: The present invention involves a gel casting and electrophoresis device that simplifies the gel cassette casting and electrophoresis process by providing an integral frame assembly that includes a bottom sealing means movable to a first position where the sealing means seals the bottom of the gel cassette for gel casting purposes and a second position which exposes the bottom of the gel cassette for electrophoresis purposes.

Abstract: A well-forming and loading-guide comb for electrophoresis gels. The comb includes a comb body, to which well-forming teeth and a loading guide are attached in an opposing fashion. The comb can be used with the teeth pointing downward into the gel to form sample wells in either vertical or horizontal electrophoresis gels. Upon hardening of the gel, the comb is once removed from the gels, leaving sample wells therein. The comb is then rotated 180 degrees, and notches (in the case of vertical electrophoresis gels) or L-shaped extensions (in the case of horizontal electrophoresis gels) of the loading guide are aligned with the sample wells so as to provide for easy guided access of a sample delivering instrument during the loading of samples into the wells.

Abstract: An apparatus for efficiently circulating and moving a fluid across a workpiece. The apparatus can provide for the automated handling of the fluids used, and is well suited for use in the staining and fixing of biological assays such as electrophoresis gels. The tray of the invention includes first and second side walls, first and second end walls, a first curved wall portion connecting the first side wall and the first end wall, and a second curved wall portion connecting the second side wall and the second end wall. The inclusion of the curved surface in the combination causes mixing to occur efficiently when the tray is "rocked" from side to side as in the conventional apparatus. Thus, the apparatus of the invention may also include a motor for alternately raising and lowering each end wall of the tray in a rocking motion, thereby causing the fluid to alternately flow towards and away from each end wall.

Abstract: A generally circular mass spectrometer and ion filters used therein have hyperbolic pole pieces which can be machined by diamond turning. In a quadrature assembly, two pole segments can be identical and provide the outer arcuate pole surfaces, and two segments can be identical and provide the inner arcuate pole surfaces opposite from the outer pole surfaces. A support plate has an arcuate outer surface which engages alignment surfaces of the pole segments, the alignment surfaces and outer support surfaces being machined by turning. In a quadrapole, one outer pole piece and one inner pole piece are mounted on each support surface of the plate with the alignment surfaces in abutment with the support plate outer surface for accurate alignment. An outer pole segment on one support surface is electrically connected to an inner pole segment on the opposing support surface. Each support segment has a plurality of spokes for mounting to the support plate.

Abstract: The invention relates to an ion filter and a method for the production of the ion filter. The ion filter comprises a plurality of elongated solid, rod assemblies. Typically, four rod assemblies, corresponding to four rod electrodes, are utilized. Each rod assembly has a curved rod surface, and at least two abutment surfaces. In one embodiment, the rod is hyperbolic in curvature. These surfaces are formed with one profiled grinding tool simultaneously in such a manner and angle of contact from a processing direction such that no undercuts are formed from this processing direction. The abutment surfaces are shaped such that one abutment surface of one rod assembly can be aligned with another abutment surface of another rod assembly when the rod surfaces are directed toward a longitudinal axis located in the interior of the ion filter. The rod assemblies are electrically insulated from each other with an insulating piece adhesively bonded to each rod assembly.