In sorbent sampling, what is sorbent breakthrough?

• A. Saturation of sorbent causing contaminants to pass through
• B. Longer sampling times prevent breakthrough
• C. Backup sorbent is unnecessary
• D. Different media are not helpful

Answer: (D)

Breakthrough in sorbent sampling occurs when the sorbent’s adsorption capacity is exceeded during sampling, so contaminants begin to pass through the sorbent bed and may appear downstream or on a backup sorbent. This means you’re no longer collecting all the analyte in the first sorbent, leading to underestimation or loss of the target compound if nothing traps it afterward. Whether breakthrough happens depends on factors like how much contaminant is present, the air flow rate, the total sampled volume, and the properties of the analyte relative to the sorbent’s capacity. To prevent it, choose a sorbent with enough capacity for the expected load, keep the sampling volume within the sorbent’s breakthrough volume, and use a backup sorbent stage so any material that passes through is still captured. Using different media can broaden the range of compounds captured and provides a check for breakthrough, so the idea that different media are not helpful isn’t accurate.