A gas chromatograph is provided with: a sample gas generator (2) configured to generate a sample gas from an injected sample; a separation column (6) fluidly connected to an outlet of the sample gas generator, the separation column (6) being configured to separate components in the sample gas generated by the sample gas generator (2); a detector (8) fluidly connected to an outlet of the separation column (6), the detector (8) being configured to detect the components separated in the separation column (6); a plurality of gas supply sources (12A, 12B) each configured to supply a carrier gas for carrying the sample gas generated by the sample gas generator to the separation column (6); a switching unit (12A, 12B) fluidly connected to the plurality of gas supply sources, the switching unit being configured to switch such that one of the plurality of gas supply sources is fluidly connected to the sample gas generator (2); a regulator (16) interposed between the switching unit (14) and the sample gas generator (2), the regulator (16) being configured to regulate a gas supply pressure from the gas supply source (12A, 12B) and a gas supply flow rate to the sample gas generator (2); and a control unit (30) configured to control an operation of the regulator (16), wherein the control unit (30) is configured such that in a case where the gas supply source fluidly connected to the sample gas generation unit has been changed in order to shift to a standby state capable of performing subsequent sample analysis and that at least a gas type of the carrier gas supplied to the supply gas generation unit (2) has been changed, the control unit (30) performs a replacement promotion operation for putting the gas supply pressure, the gas supply flow rate, or a combination thereof to a state different from the standby state to promote a gas replacement in the flow path for the carrier gas.

A di(2-ethylhexyl) terephthalate composition is provided. The di(2-ethylhexyl) terephthalate composition comprises di(2-ethylhexyl)terephthalate, at least one of a first component, a second component and a third component, and a fourth component When the di(2-ethylhexyl) terephthalate composition is characterized by gas chromatography (GC), the first component is eluted at a retention time ranging from 4.8 minutes to 6.0 minutes, the second component is eluted at a retention time ranging from 9.0 minutes to 10.0 minutes, the third component is eluted at a retention time ranging from 10.1 minutes to 12.0 minutes, and the fourth component is eluted at a retention time ranging from 21.0 minutes to 22.1 minutes. The ratio of the total area of the chromatographic peaks indicating the first component, second component, and third component to the area of the chromatographic peaks indicating the fourth component is 0.135 to 1.720.

A method for extracting an analyte from a solid sample is described. The sample is sealed in a porous membrane bag, which is sonicated in an organic solvent. An extract of the analyte forms in the bag and diffuses into the organic solvent. The organic solvent containing the extract may then be concentrated and analyzed for an analyte with gas chromatography-mass spectrometry. The method does not the use of a solid sorbent material, and does not require a step of centrifuging or filtering.

A BID includes: a discharger (2) including a dielectric pipe (8) and a pair of electrodes (14, 16) attached on an outer wall of the dielectric pipe, the pair of electrodes (14, 16) being arranged at a distance from each other in a direction along a central axis of the dielectric pipe (8), the discharger (2) being arranged so that plasma generating gas is introduced from a first end of the dielectric pipe (8) and configured to generates dielectric barrier discharge inside the dielectric pipe (8) to generate plasma; a detection section (4) including a sample gas introduction section (31) and a collection electrode (26) for collecting ions, the detection section (4) being configured to ionize components in the sample gas using light emitted from the plasma generated in the discharger (2) and to detect the generated ions by collecting them using the collection electrode (26); and a voltage supply (6; 6′) for generating a potential difference between the pair of electrodes (14, 16).

A fluid modulator includes a fluid manifold, fluid valve, and pressure/flow controller. The manifold may include a primary tee, exhaust tee, secondary tee, loop conduit, and joining tube. The valve may include a common port, normally-open output port connected to the secondary tee, and normally-closed output port connected to the primary tee. The controller may be configured to provide auxiliary fluid to the common port. In embodiments, the primary tee, exhaust tee, and secondary tee are configured with the primary tee and secondary tee situated at ends of the fluid manifold and the exhaust tee disposed therebetween. In other embodiments, the exhaust tee, the primary tee, and the secondary tee are distributed in a linear fashion with the exhaust tee and secondary tee situated at ends of the fluid manifold and the primary tee disposed therebetween. An embodiment with a single, unitary 5-port fluid manifold is also disclosed.

A method for anomaly detection and diagnosis in a chromatography system including a sample handling unit, a chromatographic separation unit, and a detection unit is disclosed. The method can include performing, with the chromatography system, a chromatography analysis of a sample to obtain a chromatogram of the sample, the sample including a known quantity of a reference standard. The method can also include determining peak information corresponding to the reference standard in the chromatogram and determining whether the peak information conforms with an expected response of the chromatography system associated with the reference standard. If the peak information does not conform with the expected response, the method can include determining that there is an anomaly in the operation of the chromatography system and diagnosing a cause of the anomaly as relating to the operation of at least one the sample handling unit, the chromatographic separation unit, and the detection unit.

An analytical system and method for detecting volatile organic chemicals in water including a coated SAW detector that provides for improved reduction of moisture at the coating of the SAW detector. A stabilized SAW sensitivity and long lasting calibration is achieved. The analytical system further includes an improved sample vessel and sparger that allow for easy grab sample analysis, while also providing efficient purging of the volatile organic compounds from the water sample. In addition, an improved preconcentrator provides a stabilized sorbent bed.

A gas chromatograph that includes a metering chamber, two separating devices and a multiport valve unit having switching functions for metering, straight separation, cutting and backflush, where the multiport valve unit is formed as a multiport diaphragm valve.

A hybrid device comprising Metal Oxide Sensors in a Gas Chromatography column is described, whereby the readings from the MOS devices will vary along the column in reaction to the sample reflecting the differential delays imposed on the components of the sample depending on the elutive effect of the adsorbent lining the column for the respective component. By this means, a family of readings is obtained, any one of which may be easier to interpret for a particular sample, and which may be compared amongst themselves providing an additional measurement dimension. The behaviour of later sections of column or sensors may be modified dynamically during a measurement cycle depending on the readings obtained at the earlier stages.

A trace detection device including: an ion mobility tube ; a sampling gas path module ; a sample injection gas path module configured to introduce a sample carrier gas containing a sample collected by the sampling gas path module toward the ion mobility tube; and a gas chromatography apparatus capable of pre-separating the sample carrier gas, so as to form a pre-separated sample carrier gas; wherein the sample injection gas path module is further configured to be capable of switching between a first mode and a second mode, in the first mode, the sample injection gas path module introduces the sample carrier gas into the ion mobility tube; and in the second mode, the sample injection gas path module introduces the sample carrier gas into the gas chromatography apparatus to pre-separate the sample carrier gas, and the pre-separated sample carrier gas is introduced into the ion mobility tube.