Compact dehydration and trap module

A gas detection device for detecting volatile organic compounds in a sample gas, comprising:

• a dehydration unit configured to dehydrate the sample gas flowing into the dehydration unit by condensation, the dehydration unit comprising a first port;
• a concentration unit arranged downstream of the dehydration unit in a flow direction of the sample gas and in fluid communication with the dehydration unit, the concentration unit comprising a second port;
• and
• a temperature control unit for controlling a temperature,
• wherein the gas detection device includes a sampling mode, in which the sample gas flows into the dehydration unit through the first port and flows out of the concentration unit through the second port, wherein the volatile organic compounds in the sample gas are concentrated in the concentration unit, and the temperature control unit is configured such that the temperature of the sample gas after flowing out from the dehydration unit and before flowing into the concentration unit is not greater than a first preset temperature set by the temperature control unit for the concentration unit,
• wherein the gas detection device further comprises an analysis unit for analyzing the volatile organic compounds, and includes a desorption mode, in which a carrier gas flows into the concentration unit from the second port, such that the volatile organic compounds desorbed from the concentration unit flows to the analysis unit with the carrier gas,
• wherein the dehydration unit comprises a reduced-diameter portion that has a reduced diameter in the flow direction of the sample gas, and in the sampling mode, the sample gas flows out of the dehydration unit through the reduced-diameter portion, and in the desorption mode, a part of the carrier gas can flow into the dehydration unit through the reduced-diameter portion for branch-off.