Which statement correctly contrasts sorbent tubes with filters in air sampling?

• A. They concentrate VOCs for laboratory analysis.
• B. They capture particulates directly from air.
• C. They measure humidity in the sample.
• D. Sorbent tubes concentrate VOCs for laboratory analysis; filters collect particulates.

Answer: (D)

The main idea here is understanding what each sampling device is meant to target. Sorbent tubes are designed to capture and concentrate volatile organic compounds (VOCs) from the air so they can be analyzed later in the lab; the sorbent material adsorbs or absorbs the vapor-phase compounds as air is drawn through the tube, concentrating them for sensitive analysis. Filters, on the other hand, are used to physically capture particulates from the air, such as dust or aerosols, for mass measurement or chemical analysis of the collected solids.

So the best statement is the one that captures both roles: sorbent tubes concentrate VOCs for laboratory analysis, while filters collect particulates. That contrast is what distinguishes their functions in air sampling.

Humidity measurement isn’t the purpose of either device, and while sorbent tubes are used for VOCs and filters for particulates, the paired contrast in the correct statement makes it the right choice.