Abstract: A calorimeter includes a bucket cover which is used to reconfigure an isothermal water reservoir to provide for temperature equilibration prior to sample analysis and subsequently define a fixed volume of water during analysis in which high precision temperature measurements can be recorded. The apparatus includes mechanisms for sealing and controlling the cover, and for coupling the combustion vessel to the cover while minimizing the thermal contact between them. Improved thermal isolation between the fixed volume of water and the surrounding environment is also achieved.

Abstract: A method of correcting time-of-flight drift in a mass spectrometer by identifying mass spectral peaks of ions in spectra, detecting ions having substantially the same mass across spectra, determining a time-of-flight drift of the detected ions, and correcting the time-of-flight drift of the detected ions by applying a correction factor to each respective time-of-flight.

Abstract: A method of mass spectral analysis in an analytical electrostatic trap (14) is disclosed. The electrostatic trap (14) defines an electrostatic field volume and includes trap electrodes having static and non-ramped potentials. The method comprises injecting a continuous ion beam into the electrostatic field volume.

Abstract: An accumulating ion source for a mass spectrometer that includes a sample injector (328) introducing sample vapors into an ionization space (115) and an electron emitter (102) emitting a continuous electron beam (104) into the ionization space (115) to generate analyte ions. The accumulating ion source further includes first and second electrodes (108a, 108b) arranged spaced apart in the ionization space (115) for accumulating analyte ions substantially therebetween. The first and second electrodes (108a, 108b) receive periodic extraction energy potentials to accelerate packets of analyte ions from the ionization space (115) along a first axis. An orthogonal accelerator (140) receives the packets of analyte ions along the first axis and periodically accelerates the packets of analyte ions along a second axis substantially orthogonal to the first axis.

Abstract: An analytical combustion furnace has an input port for receiving a holder for an analytical sample. A purge block is coupled to the input port of the combustion furnace and has an input end for receiving the holder and a gas inlet and a gas outlet. A door selectively closes the input end of the purge block, and a pressurized seal is coupled between the purge block and the door. A source of purging gas is coupled to the gas inlet of the purge block for pressurizing the seal. The gas outlet of the purge block communicates with the seal to allow purging gas to escape the area of the seal. In one embodiment, a pressurized seal surrounds a push rod, which seal is pressurized by a purging gas to continuously purge the entry of the push rod into the purge block, thereby eliminating atmospheric contamination.

Abstract: An ion source (12, 102) for a mass spectrometer comprising an ionizer (18, 106) receiving an ionizer gas from an ionizer gas supply (16), a conditioner (20) in communication with the ionizer (18, 106), a reactor (22, 110) in communication with the conditioner (20) and adapted for communication with the mass spectrometer, the reactor (22, 110) adapted to receive a sample from a sample supply in communication with the reactor (22, 110), wherein the conditioner (20) is sized to remove fast diffusing electrons from a flow of the ionizer gas from the glow discharge ionizer (18, 106) to the reactor (22, 110).

Abstract: An open electrostatic trap mass spectrometer is disclosed for operation with wide and diverging ion packets. Signal on detector is composed of signals corresponding to multiplicity of ion cycles, called multiplets. Using reproducible distribution of relative intensity within multiplets, the signal can be unscrambled for relatively sparse spectra, such as spectra past fragmentation cell of tandem mass spectrometer, past ion mobility and differential ion mobility separators. Various embodiments are provided for particular pulsed ion sources and pulsed converters such as orthogonal accelerators, ion guides, and ion traps. The method and apparatus enhance the duty cycle of pulsed converters, improve space charge tolerance of the open trap analyzer and extends the dynamic range of time-of-flight detectors.

Abstract: A method, apparatus and algorithms are disclosed for operating an open electrostatic trap (E-trap) or a multi-pass TOF mass spectrometer with an extended flight path. A string of start pulses with non equal time intervals is employed for triggering ion packet injection into the analyzer, a long spectrum is acquired to accept ions from the entire string and a true spectrum is reconstructed by eliminating or accounting overlapping signals at the data analysis stage while using logical analysis of peak groups. The method is particularly useful for tandem mass spectrometry wherein spectra are sparse. The method improves the duty cycle, the dynamic range and the space charge throughput of the analyzer and of the detector, so as the response time of the E-trap analyzer. It allows flight extension without degrading E-trap sensitivity.

Abstract: A combustion tube comprises a generally cylindrical body with an outwardly extending annular tube stop spaced from one end of the combustion tube for engaging a combustion tube mounting assembly and fixing the tube in a precise position. Near the opposite end of the tube is an enlarged opening for receiving an upper seal assembly of a combustion furnace with the outer annular shoulder of the upper end of the tube having a rolled edge to facilitate the insertion of the tube through the seal in the upper seal assembly of the furnace. The combustion tube is made of quartz glass to withstand the temperatures encountered in the furnace. The combustion tube is specifically designed and adapted to be precisely positioned in an induction furnace with an easy tube removal system for the furnace.

Abstract: Ion manipulation systems include ion repulsion by an RF field penetrating through a mesh. Another comprises trapping ions in a symmetric RF field around a mesh. The system uses macroscopic parts, or readily available fine meshes, or miniaturized devices made by MEMS, or flexible PCB methods. One application is ion transfer from gaseous ion sources with focusing at intermediate and elevated gas pressures. Another application is the formation of pulsed ion packets for TOF MS within trap array. Such trapping is preferably accompanied by pulsed switching of RF field and by gas pulses, preferably formed by pulsed vapor desorption. Ion guidance, ion flow manipulation, trapping, preparation of pulsed ion packets, confining ions during fragmentation or exposure to ion to particle reactions and for mass separation are disclosed. Ion chromatography employs an ion passage within a gas flow and through a set of multiple traps with a mass dependent well depth.

Abstract: An analyzer with a combustion furnace includes a flow path of byproducts of combustion coupled to a bidirectional ballast chamber by valves which are sequentially actuated for alternately filling and exhausting byproducts of combustion from opposite sides of the chamber during combustion. Alternately, a plurality of low volume ballast chambers are employed. A method of determining the concentration of elements in a sample includes the steps of combusting a sample; and alternately collecting and exhausting the byproduct gases of combustion in opposite sides of a bidirectional ballast. The bidirectional ballast chamber has an outer wall defining a chamber with sealed enclosures at opposite ends of the wall, a movable piston positioned within the chamber, and gas ports associated with the chamber on opposite sides of the piston.

Abstract: A crucible handling shuttle includes a pair of opposed dual crucible-gripping arms mounted on a rotatable head and moves between an induction furnace pedestal and a crucible loading station, such that one pair of arms pick up a crucible loaded with a preweighed sample, the shuttle moves to the induction furnace, where the other pair of arms grip and remove a spent crucible. The shutter head then rotates to deposit the new sample-holding crucible onto the pedestal and subsequently moves out of the furnace area to a sample disposal chute positioned between the crucible loading station and the furnace, whereupon the spent crucible is dropped for disposal. The shuttle head is then rotated and moved to the loading station to pick up a new crucible.

Abstract: A crucible handling shuttle includes a pair of opposed dual crucible-gripping arms mounted on a rotatable head and moves between an induction furnace pedestal and a crucible loading station, such that one pair of arms pick up a crucible loaded with a preweighed sample, the shuttle moves to the induction furnace, where the other pair of arms grip and remove a spent crucible. The shutter head then rotates to deposit the new sample-holding crucible onto the pedestal and subsequently moves out of the furnace area to a sample disposal chute positioned between the crucible loading station and the furnace, whereupon the spent crucible is dropped for disposal. The shuttle head is then rotated and moved to the loading station to pick up a new crucible.

Abstract: An analytical induction furnace and method for combusting conductive sample materials (500) utilizing a crucible for holding a sample within the induction furnace. Less than one gram of accelerator material is then inserted into the crucible with the sample and the induction furnace is activated for a predetermined time period (503) for thoroughly combusting the sample and accelerator. In some instances, no accelerator is required with the sample at frequencies of approximately 4.5 MHz. The invention provides for the induction furnace that is actuated in an RF frequency range between 2-9 MHz with little to no accelerator for thoroughly melting the sample for use in an analytical instrument.

Abstract: A transformer assembly (300) for use with an internal load (307) includes a transformer core (323) having a primary winding (405). A first electrode (303) and second electrode (319) are used for contacting an internal load (307). A secondary circuit is formed that includes the first electrode (303), the second electrode (319) and conductors (301,313, 317) positioned between the first electrode (303) and second electrode (319). The transformer assembly (300) is arranged so that the conductors (301, 313, 317) surround the primary winding (405), transformer core (323), the first electrode (301) and second electrode (319). The transformer assembly (300) may be used in an electrode furnace or other high current and voltage applications requiring high efficiency in a small package.

Abstract: A pulse-width-modulated voltage is applied to an IR emitter during the on-time of a primary drive voltage having a frequency of about 2.5 Hz in order to control the power to a predetermined desired level. The secondary modulation is at about 800 Hz. The lower response time of the emitter will, in effect, filter the higher frequency, and it will appear that an average power is being applied to the emitter during the on-time.

Abstract: An improved sample handling carousel is mounted to an analytical furnace at an acute angle and includes sample holding cavities which are readily visible at eye level to an operator. The rotary carousel can be easily removed from a stepwise driven drive shaft for filling the carousel at a remote location, such as a weighing station, or can be filled directly while mounted on the drive shaft. A tray is positioned below the carousel and has a slot for dropping a sample when one of the sample holding cavities aligns with the slot in the tray. In a preferred embodiment of the invention, the carousel is made of aluminum or a transparent polymeric material, such as acrylic.

Abstract: An electrode for a resistance analytical furnace has a crucible-engaging surface and an end spaced from the crucible-engaging surface having a plurality of grooves formed therein. A manifold mounted on the end of the electrode defines a dust recovery plenum and includes an outlet communicating with the plenum for coupling to a vacuum source to remove debris from the electrode. The improved electrode and electrode cleaning manifold positioned on the electrode provides a turbulent airflow for removal of dust and debris from an analytical furnace.

Abstract: A final scrubber in the inert carrier gas flow path of an elemental analyzer includes a manifold with valves for selectively bypassing a quick disconnect final scrubber housing that includes a filter tube and sealed gas fittings. The housing includes alignment members and a latch for positioning and locking the housing onto and in sealed engagement with the instrument's manifold. A switch detects the presence of the housing, and a control circuit controls valves to direct the inert gas flow though the filter tube or bypass the filter tube when the housing is removed. With this system, the final scrubber can be removed and replaced quickly without the use of tools while the carrier gas continues to flow though the furnace without interruption. Also, the valves can be closed to allow for segmented leak detection of the instruments gas flow path.