Abstract: This invention is a method and device for use with multi-dimensional chromatography that utilizes partial modulation. An analyte-bearing sample is subjected to a first dimension of chromatography. Thereafter the separated analyte-bearing sample is diluted with a modulated second carrier such at the analyte-bearing sample is not stopped or its temperature altered. The partially modulated analyte-bearing sample then feeds into a secondary column where the analyte-bearing sample is further separated.

Abstract: A chemical, biological, radiological, and nuclear weapon detection system is disclosed that comprises an array of spatially-disparate hazardous material sensors and an array of spatially-disparate video cameras. The telemetry from the sensors and the video feed from the cameras are all fed back to a centralized system control center. When the illustrative embodiment suspects that an attack has occurred, it switches the feed from the video cameras in the vicinity of where the attack is believed to occur to a monitor. This enables the personnel who monitor the illustrative embodiment to further verify the attack.

Abstract: A more efficient method for combustion or oxidation of samples containing nitrogen, phosphorus and/or sulfur to their corresponding oxides is disclosed, where method uses multi-staged addition of an oxidizing agent to enhance oxidation and liberation of nitrogen, phosphorus and/or sulfur oxides for subsequent detection. The method of the present invention allows for the injection of larger samples or the introduction of a greater amount of sample per unit of time which results in a larger amount of analyte being delivered to the detector per unit of time, thereby improving detection limits and detection efficiency.

Abstract: The invention includes a method and apparatus for a chromatography system having a chromatographic column for separating gases in a mixture from one another and an electrochemical gas sensor coupled to the chromatographic column for detecting a gas being emitted from the column. The electrochemical gas sensor further includes a substrate having a surface for depositing electrodes thereon, an ionomer membrane in contact with the surface, an electrode in contact with the surface, and an opening in the ionomer membrane in a location proximate to the electrode for permitting a gas to diffuse through the opening to simultaneously contact the electrode and the ionomer membrane within the opening.

Abstract: The invention relates to a method and apparatus for providing a reactor having a heater, a passage for transporting a reactant, and a chamber containing a gas sample and being coupled to the passage for receiving the reactant and mixing the reactant with the gas sample. The reactor further includes a connector leading from the chamber to the heater for transporting a mixture of the reactant and gas sample, and wherein the heater heats the mixture of the reactant and gas sample.

Abstract: The invention relates to a vaporizer tube for vaporizing liquid samples in capillary gas chromatography. The vaporizer tube is open throughout its whole length. It has throats which are shaped to provide, in their region, a heavy increase of the flow velocity of the carrier gas, which flows substantially unrestrictedly through the vaporizer tube. This increase of the flow velocity causes, in accordance with Bernoulli's law, reduction in pressure. Due to this pressure reduction, the easily volatile solvent is predominantly volatilized. This vaporized solvent is carried along by the carrier gas flow. The solvent can then be removed through an outlet of the sample inlet chamber. The sample proper is vaporized in the larger diameter, low velocity zones between the throats by heating the vaporizer tube and are fed to the capillary column, after the solvent has been volatilized. Thus the vaporizer tube with a plurality of throats acts like a multi-plate column.

Abstract: A thermal conductivity detector includes separate sample gas and reference gas chambers. Each chamber has a gas inlet and a gas outlet and a sensor. The chambers are connected by at least one passageway. For example, a passageway can extend from the sample gas chamber to the reference gas chamber adjacent the gas inlets. As a further example, a passageway can be provided adjacent the gas outlets. More specifically, an exhaust passageway extends from the first passageway to the additional passageway and there is an exhaust outlet connected to the additional passageway.

Abstract: An apparatus, system and method reduce the cool down time of GC ovens by supplying larger volumes of air through oven intake ducts. The system and method provide intake cross-sheets in an oven intake duct to reduce airflow spin, increasing the flow rate of fresh air into the GC oven and reducing the overall cool-down time of the GC oven. In addition, because the improved airflow allows the oven wall temperature to quickly match the oven air temperature, the noise in the temperature signal may be reduced. As a result, the GC oven can reach an equilibrium “ready” state faster. Furthermore, the utilization of the cross-sheets may allow for flexibility in the design of a fast GC oven—specifically in the location and shape of the intake duct—without loss of performance. This flexibility may become increasingly significant as GC ovens continue on the trend of becoming smaller and faster.

Abstract: A coupling device connecting the output of a microchromatograph (?CG) to the input of a mass spectrometer (MS), said coupling device comprising a capillary tube with one end connected in sealed fashion to the source under vacuum of the mass spectrometer through the intermediary of an interface device, and with the other end connected to the output of the microchromatograph, in slack fashion, open to the atmosphere; the length and the diameter of the capillary tube being chosen such that the flow rate inside the capillary tube is very close to the flow rate at the output from the microchromatograph; the interface device being, furthermore, provided with heating means for very precise adjustment of the flow rate registered by the capillary.

Abstract: Screening of items for the presence of contaminants, such as explosives residue, is accomplished by subjecting an item loaded into a pressure chamber to a pressure substantially in excess of atmospheric pressure conditions and rapidly decompressing the item to the ambient atmospheric pressure. The rapid decompression serves to scavenge vapors and particles from the exterior and interior of the item and any objects it contains. A sample of the vapors and particles removed from the item by the rapid decompression is sampled and is tested to determine whether a predetermined contaminant is present in the sample. Depending on the types of contaminants for which the sample is tested, it is possible to detect whether explosives, biological or chemical agents, and/or narcotics residues are present on or in the item being screened.

Abstract: This invention relates to a modulator for use in gas chromatographic analysis, adopted for alternatively trapping and releasing fractions of solutes in a length of a capillary column within a chromatographic oven, characterized in that it comprises at least one nozzle placed to spray at least one jet in at least one corresponding place along said capillary column length, said nozzle(s) being connected each to a source of liquid CO2 via a related valve, and means for alternatively opening said valve(s) for a predetermined time, to cause a jet of liquid CO2 to impinge for said predetermined time on said column place and to leave the oven atmosphere to heat said column place after said predetermined time. The modulator can be used in a conventional GC system or in a two dimensional GC system, for modulating the analytes fed to the second capillary column.

Abstract: An auxiliary modular oven assembly for use with a gas chromatograph. The auxiliary oven assembly is comprised of a housing, an oven compartment, a heater, at least one sampling valve, at least one fixed volume sample loop, and at least one chromatograph column or column trains, wherein the column or column trains contains a material capable of causing the separation of chemical components of a chemical sample at elevated temperatures.

Abstract: A device (1) for use in measuring and/or analyzing at least one parameter of an external portion of a body comprises at least one surface (3) configured to be placed in the vicinity of said external portion. The device is either a) configured to be able to be modeled over said external portion and made of a material comprising inorganic material, or b) configured to not be able to be modeled over said external portion and made essentially of at least, one inorganic material. When the device (1) is configured to not be able to be modeled, and when material defining the surface (3) is not in at least one of a fibrous form and a particulate form, the surface comprises an inorganic material other than glass.

Abstract: A method and an apparatus for analyzing endocrine-disrupting substances in a vital sample, comprising on-line connecting a gel permeation chromatography (GPC) column and a gas chromatographmass spectrometer (GC/MS) via line change-over means, passing a vital sample solution containing endocrine-disrupting substances through the GPC column to remove high molecular weight components and water content, accumulating the remaining low molecular weight fractions in the line, and then introducing the fractions all at once into GC/MS to automatically analyze the fractions.

Abstract: A field flame ionisation gas chromatograph for the analysis of a hydrocarbon gas mixture found in particular in mud from oil drilling and sampled by a gas carrier, which is characterised by the fact that it includes a first and a second analysis unit working in parallel simultaneously, the first analysis unit being dedicated exclusively to the analysis of methane and ethane.

Abstract: This invention relates to a modulator for use in gas chromatographic analysis, adapted for alternatively trapping and releasing fractions of solutes in a length of a capillary column within a chromatographic oven, characterized in that it comprises at least one nozzle placed to spray at least one jet in at least one corresponding place along said capillary column length, said nozzle(s) being connected each to a source of liquid C02 via a related valve, and means for alternatively opening said valve(s) for a predetermined time, to cause a jet of liquid C02 to impinge for said predetermined time on said column place and to leave the oven atmosphere to heat said column place after said predetermined time. The modulator can be used in a conventional GC system or in a two dimensional GC system, for modulating the analytes fed to the second capillary column.

Abstract: A gas chromatograph with a chromatography unit (1) for chromatographic separation and analysis of a sample (2) and with a supply unit (3) that supplies the chromatography unit (1) at least with the sample (2) and with carrier gas (4). The two units (1, 3) can be interconnected via a connection interface (7), which is equipped with a gas connector (8) for the sample (2) supplied to the chromatography unit (1), a gas connector (9) for the carrier gas (4) supplied to the chromatography unit (1) and a sealing chamber (14) receiving the gas connectors (8, 9). The sealing chamber is purged with the carrier gas (4′, 4″, 4′″) that is used in the chromatography unit (1) for separation and is provided with an outlet (22) for the carrier gas (4, 4″, 4′″).

Abstract: A transport device for transporting an analyte from a gas chromatograph into a detector has a transfer line, connectable on its outlet side to the detector, and connected on its inlet side to a connection part which is connectable to a separating column of the gas chromatograph. An auxiliary gas connection feeds an auxiliary gas into the transfer line. Gas flowing out of the separating column into the transfer line is mixable with the auxiliary gas feed through the auxiliary gas connection, and a temperature profile which falls along the transfer line toward the detector is produced during measurement by a heating device acting on the transfer line.

Abstract: In a liquid chromatograph mass spectrometer, chromatogram data is obtained by carrying out alternately a mass scan in a molecular ion detection mode and a mass scan in a fragment ion detection mode, obtaining the chromatogram data by adding spectrum intensities in the mass spectrum data obtained at the respective mass scans, and further adding sums of the spectrum intensities. Since the chromatograms in both modes are averaged, even if there is a difference in baseline levels therebetween, a chromatogram in a normal form can be obtained.

Abstract: A highly sensitive electronic ion cell for the measurement of trace elements in He carrier gas which involves glow discharge. A constant wave (CW) stable glow discharge detector which is controlled through a biased resistor, can detect the change of electron density caused by impurities in the He carrier gas by many orders of magnitude larger than that caused by direct ionization or electron capture. The stable glow discharge detector utilizes a floating pseudo-electrode to form a probe in or near the plasma and a solid rod electrode. By using this probe, the large variation of electron density due to trace amounts of impurities can be directly measured. The solid rod electrode provides greater stability and thus easier alignment.

Abstract: A gas chromatography system having a computer-controlled venting valve system that delivers pressurized pulses to a column junction point of two series-coupled columns having different stationary-phase chemistries and a method of using the same. Each pressurized pulse causes a differential change in the carrier gas velocities in the two columns, which lasts for the duration of the pressurized pulse. Whereby, the pressurized pulse selectively increases the separation of a component pair that exhibits separation at the exit of the first column, but otherwise co-elutes from the column ensemble.

Abstract: A gas chromatography system having a computer-controlled pressure controller that delivers pressurized pulses to a column junction point of two series-coupled columns having different stationary-phase chemistries and a method of using the same. Each pressurized pulse causes a differential change in the carrier gas velocities in the two columns, which lasts for the duration of the pressurized pulse. Whereby, the pressurized pulse selectively increases the separation of a component pair that exhibits separation at the exit of the first column, but otherwise co-elutes from the column ensemble.

Abstract: A gas chromatography system having a computer-controlled venting valve system that delivers pressurized pulses to a column junction point of two series-coupled columns having different stationary-phase chemistries and a method of using the same. Each pressurized pulse causes a differential change in the carrier gas velocities in the two columns, which lasts for the duration of the pressurized pulse. Whereby, the pressurized pulse selectively increases the separation of a component pair that exhibits separation at the exit of the first column, but otherwise co-elutes from the column ensemble.

Abstract: This invention provides a reduced power consumption gas chromatograph system (10) which includes a capillary gas chromatograph column member (12) which contains a chemical sample to be analyzed. The gas chromatograph system further includes a heating mechanism (16) which extends throughout the length of the capillary gas chromatograph column member (12) and surrounds both the member (12) and a temperature sensing mechanism (14) which is mounted adjacent to the column member (12). The temperature sensing mechanism (14), the heating mechanism (16) and the column member (12) form a chromatograph column assembly (20) which includes a coiled section (28) where the components are tightly packed with respect to each other and allows for a reduced power consumption for temperature programming miniature gas chromatography column assemblies.

Abstract: An assembly for desorbing sampling tubes comprises a gas chromatograph known per se provided with an injector. The sampling tubes are provided with an inflow opening and an outflow opening. The assembly comprises an adapter which is placed in the injector and which is provided with a chamber which is bounded by a heat conducting housing. The adapter is arranged for placing a sampling tube in the chamber thereof, while in a condition of a sampling tube wherein it is placed in the adapter, the inflow opening thereof is in fluid communication with a first carrier gas supply duct, while the outflow opening of the sampling tube is in fluid communication via the injector with a gas chromatography column disposed in the gas chromatograph.

Abstract: An apparatus for collecting and detecting chemicals contained in a fluid includes a sorbent element, at least one chemical sensor, a first pump for pumping fluid through the sorbent element and a second pump for pumping fluid to the chemical sensor. The sorbent element contains a sorbent material and a heating element. The first pump pumps fluid into the sorbent element thereby collecting the chemicals on the sorbent material. The heating element provides heat to the sorbent element to desorb the chemicals from the sorbent material. The chemicals desorbed from the sorbent material are then pumped out of the sorbent element and to the chemical sensor. The sorbent material may have a cavity therein with the heating element located in that cavity. Alternatively, the heating element may be interposed between the enclosure and the sorbent material.

Abstract: A system for concentrating a volatile organic compound (VOC) sample uses in one embodiment a bypass line and a valve coupled thereto to regulate an amount of carrier gas flowing through a carrier gas line. A flow splitter fluidly couples the bypass line to the carrier gas line, and connects to the output of a cryofocuser. The valve opens at the onset of transferring the VOC sample from a concentrator trap such as a sorbent trap to the cryofocuser, thereby resulting in an increased amount of carrier gas flow between the concentrator trap and the cryofocuser for more efficient desorbing of the concentrator trap. The valve is closed when the focused VOC sample is flushed out of the cryofocuser for delivery to a gas chromatograph, preferably delivering the entire VOC sample to the GC.

Abstract: A sample injector valve capable of introducing multiple samples of material into multiple liquid or gas streams is provided. Such a valve is particularly useful for injecting multiple samples under pressure into a combinatorial chemistry system with moving streams of fluid, such as a parallel pressure reactor or a rapid flow analysis system using multi-channel or parallel chromatography and related techniques. The valve is further capable of functioning on a small scale with automatic sampling equipment.

Abstract: This invention relates generally to a new class of chemoselective polymer materials. In particular, the invention relates to linear and branched polysiloxane compounds for use in various analytical applications involving sorbent polymer materials, including chromatography, chemical trapping, analyte collection, and chemical sensor applications.

Abstract: The invention provides a gas chromatography method for analyzing materials vaporizable in a gas chromatograph system, the method including filling a sample injection device with a sample of the compounds to be analyzed; transferring the sample compounds into an analytical separation column with a transfer gas; passing a carrier gas inside the analytical separation column for time separation of the sample compounds; controlling the temperature of the column for achieving separation of the sample compounds; transferring the vaporized sample compounds eluted from the column into a flame ionization detector; providing the gases required for the operation of the flame ionization detector, and analyzing the data output of the flame ionization detector for analysis of the sample compounds, wherein the gases required for the operation of the gas chromatograph system are produced by water electrolysis.

Abstract: Methods for evaluating catalysts, in which a multicell holder, e.g., a honeycomb or plate, or a collection of individual support particles, is treated with solutions/suspensions of catalyst ingredients to produce cells, spots or pellets holding each of a variety of combinations of the ingredients, is dried, calcined or treated as necessary to stabilize the ingredients in the cells, spots or pellets, then is contacted with a potentially reactive feed stream or batch, e.g., biochemical, gas oil, hydrogen plus oxygen, propylene plus oxygen, CCl2F2 and hydrogen, etc. The reaction occurring in each cell can be measured, e.g., by infrared thermography, spectroscopic detection of products or residual reactants, or by sampling, e.g., multistreaming through low volume tubing, from the vicinity of each combination, followed by analysis, e.g., spectral analysis, chromatography, etc., or by observing temperature change in the vicinity of the catalyst, e.g.

Abstract: A system for analyzing samples using purge and trap concentration is provided. The system includes a plurality of purge and trap concentration units, each adapted to receive a sample and provide a focused analytic sample slug to an analyzer. An analyzer is coupled to each of the plurality of concentrators and receives the focused analytic slugs therefrom. The concentrators are operated in phases from one another.

Abstract: A method of measuring the effective temperature inside a sealed container having a headspace is provided. A liquid solvent is added to the container, and a solid compound is added to the liquid solvent to create a saturated solution. Vapor of the saturated solution is allowed to equilibrate in the headspace of the sealed container, and a volume thereof is transferred to a chromatographic column, where chromatographic readings of the equilibrated vapor are taken. A temperature within the sealed container is then calculated based upon the chromatographic readings of the equilibrated vapor, wherein the temperature calculation is based upon the concentrations of the liquid solvent and the solid compound in the equilibrated vapor.

Abstract: A passive air sampler is designed to facilitate emptying granular or particulate adsorbent from it directly into a thermal desorption tube or other vessel for use in an analytical instrument. The preferred form has an adsorbent container in a conical or funnel-like shape.

Abstract: The invention relates to a material for treating gaseous media containing volatile organic components. According to the invention, the material is porous and exhibits an absorption capacity of approximately 20-30% in relation to the dry weight thereof, containing approximately 47-52% by weight of a composite carbon and silicon structure, approximately 12-20 wt. % carbon, approximately 5-7 wt % hydroxyl, and approximately 1-2 wt % oxygen. The invention can be used in atmospheric treatment for the preservation of living matter.

Abstract: An explosion-proof apparatus includes a pressure resistant explosion-proof case, heater, manifold, and analyzer unit. The heater is disposed in the pressure resistant explosion-proof case. The manifold is heated by the heater in the pressure resistant explosion-proof case and supplies heat from the heater to an outside of the pressure resistant explosion-proof case by heat conduction. The analyzer unit is disposed outside the pressure resistant explosion-proof case in contact with the manifold, and is heated by heat supplied from the manifold.

Abstract: A method and device for determining the concentration of analytes in a sample. The device has a surface with an extraction coating thereon. The method is carried out while the sample is highly agitated to maintain a substantially constant boundary layer. The sample is brought into contact with the coating for a limited time so that all the analytes that pass through the boundary layer are adsorbed by the coating. The amount of analytes in the coating is determined and the concentration of those same analytes in the sample is then calculated from the diffusion coefficient of the analytes. The device is first calibrated using analytes of known concentration.

Abstract: A micro-gas chromatograph column is formed by texturing a channel into a plurality of green-sheet layers, which are then sintered together to form a substantially monolithic structure. A thick-film paste may be added to the channel textured in the green-sheet layers to provide a porous plug sintered in the micro-gas chromatograph column in the substantially monolithic. A thermal conductivity detector is formed in the substantially monolithic structure by depositing a conductive thick-film paste on the surface of one of the green-sheet layers to define a resistor in an exit channel of the micro-gas chromatograph column.

Abstract: A gas chromatography system having a computer-controlled pressure controller that delivers pressurized pulses to a column junction point of two series-coupled columns having different stationary-phase chemistries and a method of using the same. Each pressurized pulse causes a differential change in the carrier gas velocities in the two columns, which lasts for the duration of the pressurized pulse. Whereby, the pressurized pulse selectively increases the separation of a component pair that exhibits separation at the exit of the first column, but otherwise co-elutes from the column ensemble.

Abstract: A gas chromatography system having a computer-controlled venting valve system that delivers pressurized pulses to a column junction point of two series-coupled columns having different stationary-phase chemistries and a method of using the same. Each pressurized pulse causes a differential change in the carrier gas velocities in the two columns, which lasts for the duration of the pressurized pulse. Whereby, the pressurized pulse selectively increases the separation of a component pair that exhibits separation at the exit of the first column, but otherwise co-elutes from the column ensemble.

Abstract: A micro-machined back-flush injector that allows for a sample introduced into the injector to be properly injected into a gas chromatography apparatus in a short time period of between 10 and 100 milliseconds. A micro-machined injector having back-flushing capability that allows back-purging of unwanted components in the device and provides clean-up of channels in contact with the sample. Further, a method of operating an injector such that a sample is properly injected and purged from the system to which the injector is operably attached.

Abstract: This invention relates to a modulator for use in gas chromatographic analysis, adopted for alternatively trapping and releasing fractions of solutes in a length of a capillary column within a chromatographic oven, characterized in that it comprises at least one nozzle placed to spray at least one jet in at least one corresponding place along said capillary column length, said nozzle(s) being connected each to a source of liquid CO2 via a related valve, and means for alternatively opening said valve(s) for a predetermined time, to cause a jet of liquid CO2 to impinge for said predetermined time on said column place and to leave the oven atmosphere to heat said column place after said predetermined time. The modulator can be used in a conventional GC system or in a two dimensional GC system, for modulating the analytes fed to the second capillary column.

Abstract: The present invention relates to a method and an apparatus for analyzing trace impurities in gases, which enable to analyze a very small quantity of impurities by only a simple operation, without making the column arrangement or the structure of flow complicated. In the apparatus and the method, when the trace impurities are measured in ppb-sub ppb level by a combined analyzer which is equipped with an atmospheric pressure ionization mass spectrometer to the back of a gas chromatography, a mixed gas of various gases is used as a carrier gas or purified gases added to the gases outflowed from a gas chromatography.

Abstract: The invention is a gas chromatograph that includes a mechanism to heat the carrier gas to a temperature higher than that of the columns through which it flows. The carrier gas may be temperature programmed to achieve much the same results as the known technique of temperature programming the column.

Abstract: A modular vial autosampler has a storage area for vials containing samples to be analyzed and at least one modular sampling station. A vial transfer mechanism includes an arm having a gripper that lifts a sample vial from the storage section, and the arm moves it to a station for identification and then to a sampling station, and under central control activates the sampling station for obtaining a sample for analysis. The vial transfer mechanism gripper is movable in X, Y, and Z directions to capture and move a selected vial and includes an alignment guide for the vials. Potentiometers are used for providing signals indicating arm position and the control is provided with updated information for calibration of the potentiometers and also updated position information for the arm relative to a fixed home position is obtained.

Abstract: A gas chromatography system includes a gas chromatography oven having a door adapted for integration with gas chromatography modules which are located outside of the oven cavity. For these purposes, the oven door has module receiving openings in which the modules are secured. The gas chromatography module includes a module housing containing a main coil of the capillary column, a pair of transfer lines sleeved on the free ends of the capillary column, a heater wire wound on the transfer lines, and, optionally, a pair of chromatography connectors which extend into the oven cavity and through which the free ends of the capillary column, as well as transfer lines, projecting into the oven cavity. A wall of the GC oven has an injector port and a detector port for injection of a sample into the oven cavity and for detecting the sample constituents. Column lengths extend within the oven cavity between the module and injector and detector, respectively.

Abstract: A capillary column comprising a capillary of which the inner diameter is less than 1000 &mgr;m and a continuous porous silica gel which uniformly fills the capillary, said silica gel containing both continuous through pores having diameters ranging from 0.5-5 &mgr;m and mesopores having diameters ranging from 2-50 nm.

Abstract: The invention relates to a vaporizer tube for vaporizing liquid samples in capillary gas chromatography. The vaporizer tube is open throughout its whole length. It has throats which are shaped to provide, in their region, a heavy increase of the flow velocity of the carrier gas, which flows substantially unrestrictedly through the vaporizer tube. This increase of the flow velocity causes, in accordance with Bernoulli's law, reduction in pressure. Due to this pressure reduction, the easily volatile solvent is predominantly volatilized. This vaporized solvent is carried along by the carrier gas flow. The solvent can then be removed through an outlet of the sample inlet chamber. The sample proper is vaporized in the larger diameter, low velocity zones between the throats by heating the vaporizer tube and are fed to the capillary column, after the solvent has been volatilized. Thus the vaporizer tube with a plurality of throats acts like a multi-plate column.

Abstract: A sample inlet liner includes a novel matrix that serves to retain an injected sample. The preferred inert matrix is polytetrafluoroethylene (PTFE) that serves to retain an injected sample and is provided in lieu of a conventional packing material. The contemplated inert matrix may be selected from a range of configurations of PTFE so as to provide a supporting material capable of retaining an ample quantity of injected sample in the sample inlet liner. The contemplated matrix nonetheless provides a tortuous path for the retained quantity of injected sample so as to facilitate known injection techniques such as split/splitless injection and large volume injections.

Abstract: A method applies retention-time locking to the retention times and/or the column(s) void times of a target analyte(s) being eluted thru a multidimensional gas chromatography system. Retention time locking is applied to both standard and comprehensive multidimensional gas chromatography via the steps of adjusting column(s) head pressure in a locking multidimensional gas chromatograph system such that the measured retention times and/or void times match the known accepted. Retention time locking may be applied to either or both of the columns in a multidimensional gas chromatography system. Additionally, if the multidimensional system contains more than two columns in series, retention time locking can be applied to any or all of the columns as required.