Which statement about the vacuum system is true?

• A. The vacuum system must have a pump capable of evacuating air in chamber to 6 mm Hg at sea level.
• B. The vacuum system is optional for this procedure.
• C. Vacuum should be avoided to prevent sample damage.
• D. The vacuum system should evacuate to 60 mm Hg.

Answer: (A)

Achieving a high vacuum is essential because it removes air and moisture from the chamber, creating a controlled environment for the procedure. A pump capable of evacuating to 6 mm Hg at sea level means the system can reach a true high-vacuum condition, which minimizes the presence of air and reactive gases and helps ensure consistent, reliable results.

Reaching only 60 mm Hg would leave far too many air molecules in the chamber, leading to variability, potential moisture or gas interference, and less effective degassing or processing. This is not a feature you can skip—the procedure relies on the chamber being pumped down to a low pressure to achieve its goals. Vacuum is not something to avoid for sample protection in this context; it’s used to reduce exposure to air and moisture that could cause damage or skew results.

So, the requirement for a vacuum system that can evacuate to 6 mm Hg is the correct one.