A pretreatment method for analyzing dioxin compounds and an analytical method using the same, in which a column packed with polymer beads that are capable of selectively adsorbing dioxin compounds is used in a purification step during pretreatment, thereby remarkably reducing a time required for pretreatment and improving a recovery rate of an internal standard for purification, are provided.

A thermal conductivity detector includes a first pipe passage and an exhaust pipe passage. The first pipe passage is accommodated in a cell block together with a heating device. The exhaust pipe passage has an outlet port at the downstream end, and most of the exhaust pipe passage including the downstream end is drawn out of the cell block. The heating device maintains the space in the cell block at a temperature capable of vaporizing the sample. A filament is accommodated in the first pipe passage. The gas passing through the first pipe passage is discharged out of the thermal conductivity detector through the exhaust pipe passage outlet port. On the inner surface of the exhaust pipe passage, a coating having resistance to a cleaning fluid for removing the adhered substance due to the sample gas is formed.

A thermal conductivity detector includes a first pipe passage and an exhaust pipe passage. The first pipe passage is accommodated in a cell block together with a heating device. The exhaust pipe passage has an outlet port at the downstream end, and most of the exhaust pipe passage including the downstream end is drawn out of the cell block. The heating device maintains the space in the cell block at a temperature capable of vaporizing the sample. A filament is accommodated in the first pipe passage. The gas passing through the first pipe passage is discharged out of the thermal conductivity detector through the exhaust pipe passage outlet port. On the inner surface of the exhaust pipe passage, a coating having resistance to a cleaning fluid for removing the adhered substance due to the sample gas is formed.

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.

A system and method for surface characterization of a porous solid or powder sample using flowing gas include mass flow controllers configured to deliver a controllable mass flow of a carrier gas and adsorptive gas to vary concentration of the adsorptive gas flowing through at least one measurement channel containing a sample cell. A concentration detector downstream of the sample cell provides a signal indicative of the adsorptive gas concentration to a controller that determines the amount of adsorptive gas adsorbed and/or desorbed to characterize the surface area, pore volume, pore volume distribution, etc. of the sample material. The detector may include a housing, heat exchanger, thermal conductivity detector, and a temperature regulator.

A system and method for surface characterization of a porous solid or powder sample using flowing gas include mass flow controllers configured to deliver a controllable mass flow of a carrier gas and adsorptive gas to vary concentration of the adsorptive gas flowing through at least one measurement channel containing a sample cell. A concentration detector downstream of the sample cell provides a signal indicative of the adsorptive gas concentration to a controller that determines the amount of adsorptive gas adsorbed and/or desorbed to characterize the surface area, pore volume, pore volume distribution, etc. of the sample material. The detector may include a housing, heat exchanger, thermal conductivity detector, and a temperature regulator.

A system and method for surface characterization of a porous solid or powder sample using flowing gas include mass flow controllers configured to deliver a controllable mass flow of a carrier gas and adsorptive gas to vary concentration of the adsorptive gas flowing through at least one measurement channel containing a sample cell. A concentration detector downstream of the sample cell provides a signal indicative of the adsorptive gas concentration to a controller that determines the amount of adsorptive gas adsorbed and/or desorbed to characterize the surface area, pore volume, pore volume distribution, etc. of the sample material. The detector may include a housing, heat exchanger, thermal conductivity detector, and a temperature regulator.

A gas analyzer includes a sample inlet, a sample outlet, a detector, a monitoring component, and a controller. The sample inlet is configured to receive a sample and is coupled to the sample outlet. The detector is operably disposed between the sample inlet and the sample outlet and is configured to provide an indication relative to the sample. The monitoring component is configured to provide a diagnostic indication regarding at least one component of the gas analyzer. The controller is configured to control flow through the gas analyzer and is operably coupled to the detector to analyze the sample, provide the analysis to the monitoring component, and provide the indication of health to an output.

Examples described herein provide a method for characterizing a catalyst in a chemisorption unit. The method includes treating a catalyst sample with gas blend comprising ammonia in an inert gas and performing a first temperature programmed desorption (TPD) to desorb the ammonia from the catalyst sample. A temperature programmed reduction (TPR) of the catalyst sample is performed with hydrogen. The catalyst sample is treated after the TPR with a gas blend comprising ammonia in an inert gas. A second temperature programmed desorption is performed to desorb the ammonia from the catalyst sample.