What does a travel blank contain?

• A. ASTM Type II reagent water
• B. Groundwater sample
• C. Distilled water
• D. Air sample

Answer: (A)

Travel blanks are used to detect contamination introduced during sampling, handling, or transport. They travel with the sampling event and are analyzed to see if any contaminants come from the process rather than the environment. In practice, a travel blank is filled with a known clean water standard so that any detected contaminants point to the sampling procedure itself. The standard choice is ASTM Type II reagent water because it is a high-purity, well-characterized water that provides a reliable baseline for detecting contamination without introducing unknown substances. Groundwater sample is the actual sample being measured, while an air sample isn’t relevant for checking water sampling contamination. Distilled water could be used in some contexts, but ASTM Type II reagent water is the commonly specified option for travel blanks due to its established quality and consistency.