A travel blank accompanying groundwater samples for VOC analysis is used to do what?

• A. Calibrate the analytic instrument
• B. Detect contamination introduced during sampling or transport
• C. Provide a backup groundwater sample
• D. Measure field pH of the sample

Answer: (B)

Travel blanks are a QA/QC check in VOC groundwater sampling. They accompany real samples and undergo the same sampling, handling, and transport steps but do not contact the groundwater. The purpose is to reveal any contamination introduced during the sampling process or transport so analysts can pinpoint whether detected VOCs come from the well or from the sampling procedure itself. If compounds show up in a travel blank, it indicates potential process-related contamination that could affect interpretation of the actual samples. These blanks aren’t used for instrument calibration, they aren’t backups, and they aren’t used to measure field pH.