Abstract: A multi-dimensional gas chromatograph for analyzing compounds in a sample during a single run is disclosed. The multi-dimensional gas chromatograph includes a first column, a second column, and a modulator disposed between the first column and the second column. The modulator modulates at (i) a first modulation period over a first time period during the run and (ii) a second modulation period over a second time period during the run later than the first time, the second modulation period being different than the first modulation period.

Abstract: A method for modulating analytes in a gaseous stream passing through a capillary, wherein the analytes are retained in a trapping zone of the capillary, or allowed to pass therethrough, based on certain conditions. The method includes, during a first time period, heating the trapping zone of the capillary to a first temperature to desorb analytes therewithin and allow the analytes to pass therethrough, and during a second time period, cooling the capillary to a second temperature that is sufficient to trap and focus the analytes within the trapping zone. During the first time period, the method also includes retaining heat at the capillary during to minimize the load on a cooling device thermally connected thereto, and during the second time period, selectively allowing thermal transfer toward the cooling device.

Abstract: A time-of-flight mass spectrometer (TOF MS) comprises a mass analyzer, an ion pushing device, a filtering device, a multi-pass reflector, a detector, and a decoder. The ion pushing device is arranged to push ions into the mass analyzer. The filtering device is arranged to filter a portion of the ions based on a mass range of the ions. The multi-pass reflector is arranged to selectively reflect the ions for further passes through the mass analyzer. The detector is arranged to receive the ions. The decoder is arranged to reconstruct a mass spectrum for the entire mass range of the ions.

Abstract: An analytical instrument assembly includes a gas chromatograph, a first detector, a second detector, and a pneumatic control module. The gas chromatograph includes a flow splitter configured to receive a sample. The first detector is coupled to the flow splitter. The second detector is coupled to the flow splitter. The pneumatic control module is coupled to the flow splitter and configured to deliver a carrier gas to the flow splitter. The flow splitter is configured to split the sample and deliver at least a first portion of the sample to the first detector and at least a second portion of the sample to the second detector at a first split ratio.

Abstract: A multi-dimensional gas chromatograph for analyzing compounds in a sample during a single run is disclosed. The multi-dimensional gas chromatograph includes a first column, a second column, and a modulator disposed between the first column and the second column. The modulator modulates at (i) a first modulation period over a first time period during the run and (ii) a second modulation period over a second time period during the run later than the first time, the second modulation period being different than the first modulation period.

Abstract: A thermal modulator for a chromatographic system includes a cooler, a thermal valve, a thermal buffer, a heater, and a capillary. The thermal valve thermally-engages the cooler. The thermal buffer thermally-engages the thermal valve. The heater thermally-engages the thermal buffer. The capillary thermally-engages the heater and is configured to transport an analyte in a first direction.

Abstract: A method for ranking analytes includes the steps of analyzing an experimental analyte in a mass spectrometer. The method includes comparing the experimental analyte to a plurality of candidate analytes in a library hit list, and assigning a cumulative confidence score to each candidate analyte based on the steps of comparing the experimental analyte to the candidate analytes based on a library similarity score, comparing the experimental analyte to the candidate analytes based on of a presence of the most abundant isotope of a molecular ion and its mass, comparing the experimental analyte to the candidate analytes based on an abundance of fragment ions and a mass of the fragment ions, and, in some implementations, comparing the experimental analyte to the candidate analytes based on a retention index value. The method includes ranking the candidate analytes based on the cumulative confidence score of each candidate analyte.

Abstract: A method includes receiving respective first and second sets of detection data generated by first and second detectors of a gas chromatograph (GC) during a session and representative of chromatographic properties of first and second portions of an effluent delivered to the first and second detectors from first and second transfer lines of the GC. The method also includes receiving a temperature profile that identifies first and second temperature zones of the first and second portions of the effluent during the session. The second set of detection data is misaligned relative to the first set along a time axis. The method also includes applying an alignment profile to the second set to align the first and second sets along the time axis. The alignment profile is based on the temperature profile.

Abstract: The analyzer of the present invention is specifically adapted to provide moisture determinations for foods and other agricultural material. It allows the operator to introduce a precise weight of sample into a crucible in a closed furnace in a controlled environment through an access port in the furnace cover. The access port in the cover can be tapered to allow easy access to an underlying aligned crucible and allow an operator to add and remove sample material from the crucible until a precise desired sample weight is reached as measured by a balance within the furnace. The access port is enclosed by an insulated cover after the samples are sequentially placed in the crucibles.

Abstract: A device is provided for use in analytical instrumentation that provides continuous transfer of a known molar quantity of gas from a source having an unknown gas mixture and varying pressure. In addition to the upstream and downstream paths of typical flow control devices, the device has a midstream path to introduce a carrier gas at a known elevated pressure. The device has at least three equal-volume ballast vessels and a valve arrangement to cycle the ballasts through at least three states: fill, equilibrate, and empty. The ballasts fill with the upstream gas, pressurize and equilibrate at the midstream pressure, and empty to the downstream path. The cycle of each ballast is timed in phased relationship to the other ballasts to keep the flow relatively uninterrupted; as one fills, another equilibrates, and another empties.

Abstract: A method for modulating analytes in a gaseous stream passing through a capillary, wherein the analytes are retained in a trapping zone of the capillary, or allowed to pass therethrough, based on certain conditions. The method includes, during a first time period, heating the trapping zone of the capillary to a first temperature to desorb analytes therewithin and allow the analytes to pass therethrough, and during a second time period, cooling the capillary to a second temperature that is sufficient to trap and focus the analytes within the trapping zone. During the first time period, the method also includes retaining heat at the capillary during to minimize the load on a cooling device thermally connected thereto, and during the second time period, selectively allowing thermal transfer toward the cooling device.

Abstract: Systems and methods for processing data in a two-dimensional chromatograph are disclosed. In some implementations, the data includes information associated with resolved peaks and information associated with an unresolved complex mixture, and such systems and methods may attenuate the information associated with the resolved peaks from the data to substantially isolate the information associated with the unresolved complex mixture.

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: A rotary dosing device for use in analytical instrumentation quickly transfers a sequence of precise molar quantities of gas from a primary stream into a secondary stream. The device has a rotating chamber with dosing ports that cycle through three states: fill, equilibrate, and transfer. The device cycles in an overlapping manner such that as one dose volume fills with gas from the primary stream, another equilibrates at a known pressure and temperature, and another transfers its contents to the secondary stream. The device initiates its operation so that the first transfer in a sequence is a properly filled and equilibrated dose from the primary stream. Rather than cycling a single dose volume through the three states multiple times, the overlapping operation of the rotary doser enables multiple precise molar quantities of gas to be transferred in one-third the time.

Abstract: A voltage stabilizer assembly includes a power supply, a device, and a voltage stabilizer. The device is connected to the power supply, wherein the device performance is affected based on the regulation of its power source. The voltage stabilizer is connected between the device and the power supply. The voltage stabilizer includes a low pass filter connected to an output of the power supply and a buffer receiving its input from the low pass filter, the buffer receiving power from the power supply, and the output of the buffer connected to the device.

Abstract: A re-sampling device for two-dimensional gas chromatography includes a modulator and at least one of a first splitter disposed upstream from the modulator and configured to split an effluent from a primary column and deliver a portion of the effluent to waste and a portion of the effluent to the modulator, or a second splitter disposed downstream from the modulator and configured to split the effluent to deliver a portion of the effluent to waste and a portion of the effluent to a secondary column.

Abstract: A method for applying a heating sequence for a modulator includes, during a first period of time, heating a first heating zone disposed along a length of the modulator without heating a second heating zone to cause a sample trapped from a first transfer line at an entrance of the modulator to move from the first heating zone to the second heating zone. The method also includes, during a second time period, withdrawing the heating of the first heating zone to prevent the sample from entering the modulator from the first transfer line. During a third time period, the method includes heating the second heating zone without heating the first heating zone to reinject the sample into a second transfer line.

Abstract: A chromatography system includes a modulator, a chromatograph, a cooler, and a detector. The chromatograph is connected to the modulator by a first heated transfer line. The detector is connected to the modulator by a second heated transfer line. The cooler is connected to the modulator. The modulator is arranged outside of the chromatograph.

Abstract: A time-of-flight mass spectrometer (TOF MS) comprises a mass analyzer, an ion pushing device, a filtering device, a multi-pass reflector, a detector, and a decoder. The ion pushing device is arranged to push ions into the mass analyzer. The filtering device is arranged to filter a portion of the ions based on a mass range of the ions. The multi-pass reflector is arranged to selectively reflect the ions for further passes through the mass analyzer. The detector is arranged to receive the ions. The decoder is arranged to reconstruct a mass spectrum for the entire mass range of the ions.

Abstract: A platen for a metallographic grinder has an outer peripheral rim with an upper surface having a lower height. Also, fingers engaging a specimen are allowed to move laterally (i.e., wobble) to minimize the tipping forces on the specimen during the grinding process. Either one or both of these structures can be employed and results in a much flatter specimen surface for use in subsequent analysis.