How do sorbent tube sampling and impinger sampling differ?

How do sorbent tube sampling and impinger sampling differ?

• A. Sorbent tubes collect vapors on a solid sorbent; impingers collect in a liquid medium for analysis
• B. Impinger sampling collects in a liquid medium for analysis
• C. Both collect solids on filters
• D. Sorbent tubes measure particulates

Answer: (A)

The main idea is where the contaminant is captured and how it’s prepared for analysis. Sorbent tubes trap vapor-phase contaminants on a solid sorbent material as air passes through, so the target compounds are adsorbed onto the solid and later released (desorbed) for analysis, typically by GC or GC-MS. Impinger sampling, in contrast, captures contaminants by bubbling the air through a liquid; the contaminant dissolves or reacts in that liquid and the liquid sample is then analyzed. This fundamental difference affects what compounds can be collected, how much sample volume you can handle, and how stable the sample is during transport and storage. Sorbent tubes are common for trace VOCs and are often very stable after collection, while impingers are useful when the analyte dissolves well in a chosen liquid and you want the liquid sample ready for direct analysis.

The main idea is where the contaminant is captured and how it’s prepared for analysis. Sorbent tubes trap vapor-phase contaminants on a solid sorbent material as air passes through, so the target compounds are adsorbed onto the solid and later released (desorbed) for analysis, typically by GC or GC-MS. Impinger sampling, in contrast, captures contaminants by bubbling the air through a liquid; the contaminant dissolves or reacts in that liquid and the liquid sample is then analyzed. This fundamental difference affects what compounds can be collected, how much sample volume you can handle, and how stable the sample is during transport and storage. Sorbent tubes are common for trace VOCs and are often very stable after collection, while impingers are useful when the analyte dissolves well in a chosen liquid and you want the liquid sample ready for direct analysis.