A method for surface characterization of a porous solid or powder sample using flowing gas includes a controller that controls mass flow of a carrier gas and an adsorptive gas to form a mixture having a target concentration of the adsorptive gas over the sample, determining adsorptive gas concentration based on signals from a detector disposed downstream of the sample, automatically repeating the controlling and determining steps for a plurality of different target concentrations, and generating an isotherm for the sample based on the adsorptive gas concentration for the plurality of different target concentrations. The method may include immersing the sample in liquid nitrogen to cool the sample for all, or at least a portion of each of the different target concentrations. The target concentrations may vary from less than 5% to greater than 95%, and may vary in a stepwise manner.

A method for surface characterization of a porous solid or powder sample using flowing gas includes a controller that controls mass flow of a carrier gas and an adsorptive gas to form a mixture having a target concentration of the adsorptive gas over the sample, determining adsorptive gas concentration based on signals from a detector disposed downstream of the sample, automatically repeating the controlling and determining steps for a plurality of different target concentrations, and generating an isotherm for the sample based on the adsorptive gas concentration for the plurality of different target concentrations. The method may include immersing the sample in liquid nitrogen to cool the sample for all, or at least a portion of each of the different target concentrations. The target concentrations may vary from less than 5% to greater than 95%, and may vary in a stepwise manner.

The invention relates to a method for analysing hydrocarbons, comprising: the implementation of a gas chromatography separation according to a first controlled temperature profile, to separate a sample into a plurality of analytes; the detection of at least one of said analytes by measurement of a variation of the resonance frequency of at least one resonator of nano-electromechanical system (NEMS) type covered with a functional layer made to vibrate at the resonance frequency thereof, under the effect of an adsorption or desorption of the analyte by the functional layer, said method being characterised in that the resonator is subjected to a second controlled temperature profile, lower than the first profile.

The invention relates to a method for analysing hydrocarbons, comprising: the implementation of a gas chromatography separation according to a first controlled temperature profile, to separate a sample into a plurality of analytes; the detection of at least one of said analytes by measurement of a variation of the resonance frequency of at least one resonator of nano-electromechanical system (NEMS) type covered with a functional layer made to vibrate at the resonance frequency thereof, under the effect of an adsorption or desorption of the analyte by the functional layer, said method being characterised in that the resonator is subjected to a second controlled temperature profile, lower than the first profile.

A thermal conductivity detector (TCD) includes: a detection channel through which a gas to be measured flows as a fluid; a thermal conduction part that has a filament provided at a position in the detection channel where the filament comes into direct contact with the fluid flowing through the detection channel, thereby conducting heat through the fluid flowing through the detection channel; and a detection circuit for detecting an electric signal based on a change in a voltage or a current of the filament. The thermal conduction part has a plurality of filament sections that are substantially parallel to a flow direction of the fluid flowing through the detection channel.

A thermal conductivity detector (TCD) includes: a detection channel through which a gas to be measured flows as a fluid; a thermal conduction part that has a filament provided at a position in the detection channel where the filament comes into direct contact with the fluid flowing through the detection channel, thereby conducting heat through the fluid flowing through the detection channel; and a detection circuit for detecting an electric signal based on a change in a voltage or a current of the filament. The thermal conduction part has a plurality of filament sections that are substantially parallel to a flow direction of the fluid flowing through the detection channel.

Certain configurations of a gas chromatography system comprising an internal gas generator are described. In some instances, the gas chromatography system may comprise an internal hydrogen generator to provide hydrogen gas to a chromatography column for separation of analyte species. In certain examples, the gas chromatography system can be operated without any external gas inputs.

Certain configurations of a gas chromatography system comprising an internal gas generator are described. In some instances, the gas chromatography system may comprise an internal hydrogen generator to provide hydrogen gas to a chromatography column for separation of analyte species. In certain examples, the gas chromatography system can be operated without any external gas inputs.

Embodiments of a gas detector with a first gas sensor having a first gas specificity and a first response time and a second gas sensor having a second gas specificity and a second response time. The first gas specificity is different than the second gas specificity, the first response time is different than the second response time, or both the first gas specificity and the first response time are different than the second gas specificity and the second response time. A readout and analysis circuit is coupled to the first and second gas sensors to read and analyze data from the first and second gas sensors, and a control circuit is coupled to the readout and analysis circuit and to the first and second gas sensors to execute logic that operates the first gas sensor, the second gas sensor, or both the first and second gas sensors.

Embodiments of a gas detector with a first gas sensor having a first gas specificity and a first response time and a second gas sensor having a second gas specificity and a second response time. The first gas specificity is different than the second gas specificity, the first response time is different than the second response time, or both the first gas specificity and the first response time are different than the second gas specificity and the second response time. A readout and analysis circuit is coupled to the first and second gas sensors to read and analyze data from the first and second gas sensors, and a control circuit is coupled to the readout and analysis circuit and to the first and second gas sensors to execute logic that operates the first gas sensor, the second gas sensor, or both the first and second gas sensors.