A thermal desorption tube collection system uses a thermoelectric cooler to collect and concentrate gas samples. In some modes, the operation of the cooler is reversed to flow the concentrated sample directly into a separator such as a gas chromatography system. Components resolved in time by a thermal desorption separator accumulate in a sample cell and are analyzed by electromagnetic radiation-based spectroscopic techniques. Also presented are methods for analyzing biogas samples.

A thermal desorber assembly includes a housing and a desorption heater element mounted in the housing with a sample cavity defined between the desorption heater element and an inner wall of the housing. An outlet port is defined in the housing. A flow channel connects the sample cavity in fluid communication with the outlet port for conveying analytes from the sample cavity to the outlet port for introducing the analytes to a spectrometer.

A method for analyzing a gas includes: allowing a sample gas to be adsorbed by each of a plurality of adsorbents (70) respectively having compositions that are different from each other; allowing the sample gas to be desorbed individually from the adsorbents (70) while detecting individually the sample gas desorbed from each of the adsorbents (70) so as to acquire desorption profiles of the sample gas that are respectively unique to the adsorbents (70); and identifying the sample gas by using a group of the desorption profiles. The acquiring of the desorption profiles is carried out by detecting, individually and over time, the sample gas desorbed from each of the adsorbents (70). Each of the desorption profiles is, for example, an overtime data created from a detection signal reflecting a quantity of the sample gas.

In a process for thermally desorbing a phase material (20), in particular for conditioning a fiber for carrying out a solid-phase microextraction, the phase material (20) is heated along a temperature curve. The temperature curve of the phase material (20) during desorption includes at least one low point.

A method for detection and identification of a chemical using a preconcentrator to collect a sample of the chemical, process said sample of the chemical, and introduce said processed chemical into a chemical analysis instrument for the detection of and identification of the chemical. A system for detecting and identifying a chemical comprising a preconcentrator having at least dual concentrating elements.

A hybrid trap including a replaceable open-tubular capillary trap followed by a packed trap is used to collect, preconcentrate, and recover a sample, such as VOCs and SVOCs found in air. The capillary stage prevents losses and carryover of the heavy fraction and can also collect the particles in air that contain the heavier SVOCs, also preventing them from reaching the packed stage. The packed stage traps lighter organic compounds that are not as prone to carryover due to channeling. The capillary and packed traps together provide quantitative recovery of compounds boiling from as low as 50 C. to as high as 600 C. The sample can be directly desorbed onto the GC column, which avoids losses and contamination caused by other approaches that thermally desorb samples through transfer lines and rotary valves more remote to the GC oven.

Components resolved in time by a separator accumulate in a sample cell and are analyzed by electromagnetic radiation-based spectroscopic techniques. The sample cell can be configured for multiple path absorption and can be heated. The separator can be a gas chromatograph or another suitable device, for example a distillation-based separator. The method and system described herein can include other mechanical elements, controls, procedures for handling background and sample data, protocols for species identification and/or quantification, automation, computer interfaces, algorithms, software or other features.

A cryogenic trap for a thermal desorber includes a hollow quartz tube having a tube wall, a tube inlet, a tube outlet, and an interior passageway between the tube inlet and the tube outlet. A sorbent material is within the interior passageway, and a metal covering surrounds at least a portion of the quartz tube. The metal covering may be a metallic coating on an outer surface of the tube wall or a metal tube fitted around the quartz tube. The metal covering may be around a portion of the quartz tube adjacent the tube inlet and/or around a portion of the quartz tube adjacent the tube outlet. The metal covering may be around substantially an entirety of the quartz tube.

A fluid network controls a gaseous flow, the fluid network having several pre-concentration units including at least one first series in which the pre-concentration units are linked in series and each defined by a rank j in the series, with j ranging from 1 to m and m being greater than or equal to 2. Each pre-concentration unit of the network includes a cavity filled with an adsorbent material, at least one first fluid pathway emerging in the cavity, at least one second fluid pathway emerging in the cavity. Finally, each pre-concentration unit includes a component for heating the cavity.

An apparatus and method for producing chemielectric point-sensor systems with increased sensitivity and increased selectivity. The chemielectric sensor system includes a sensor/heater assembly, where the sensor is a chemielectric sensor whose resistance or capacitance changes upon exposure to chemical analytes. The heater functionality applies a programmed sequence of one or more thermal pulses to the sensor to quickly raise its temperature. After each thermal pulse ends the change in resistivity of the sensor is measured. Such data as a function of the pulse time and temperature are recorded and analyzed to determine the chemical composition (selectivity) and concentrations in the ambient vapor by comparison to a library dataset. The sensor operation with fast thermal pulses also allows operation at higher frequencies where the noise is lower and hence sensitivity is improved.