Why should sample containers be two thirds filled?

Why should sample containers be two thirds filled?

• A. To maximize volume
• B. To minimize volatilization
• C. To prevent contamination
• D. To ensure weight standardization

Answer: (B)

Volatile components in a sample tend to evaporate into the surrounding air. Filling the container to about two-thirds leaves a small headspace, which helps limit how much vapor can escape during handling, shipping, and storage. The higher the liquid level, the more of the surface is exposed to air and the more opportunity there is for volatiles to migrate out when the container is opened or warmed. Leaving too little headspace can cause sealing or expansion issues, while too much headspace increases potential loss of volatile constituents. So this fill level is chosen to minimize volatilization while still allowing for safe sealing and slight expansion. Other options don’t directly address vapor loss.

Volatile components in a sample tend to evaporate into the surrounding air. Filling the container to about two-thirds leaves a small headspace, which helps limit how much vapor can escape during handling, shipping, and storage. The higher the liquid level, the more of the surface is exposed to air and the more opportunity there is for volatiles to migrate out when the container is opened or warmed. Leaving too little headspace can cause sealing or expansion issues, while too much headspace increases potential loss of volatile constituents. So this fill level is chosen to minimize volatilization while still allowing for safe sealing and slight expansion. Other options don’t directly address vapor loss.