More Questions from Physical and Chemical Agents

Which of the following items is suitable for sterilization by dry heat (hot air oven)? (Select the material that tolerates high temperature without moisture.)

Microbiology Physical and Chemical Agents Difficulty: Easy
Choose an option
  • A
    Intravenous (IV) solution
  • B
    Plastic IV bags
  • C
    Glass pipettes
  • D
    rubber gloves

Answer

Correct Answer: Glass pipettes

Explanation

Introduction: Dry heat sterilization (e.g., 160–170 °C for 2 hours) is ideal for moisture-sensitive, heat-stable items such as glassware and metal instruments. This question asks you to pick the appropriate item.

Given Data / Assumptions:

  • Dry heat destroys by oxidative processes and requires higher temperatures and longer times than steam.
  • Liquids and many plastics are unsuitable for dry heat.
  • Glass tolerates high temperatures without deformation.

Concept / Approach: Match the sterilization method to material tolerance. Glass pipettes withstand hot air oven temperatures, achieving sterility without moisture. Fluids and many polymers are better processed by moist heat or low-temperature gas methods.

Step-by-Step Solution: Eliminate liquids (IV solution) that would evaporate/overheat in dry heat. Eliminate heat-sensitive plastics and rubber (IV bags, gloves). Identify glass pipettes as hot-air-compatible. Select “Glass pipettes.”

Verification / Alternative check: Lab SOPs routinely sterilize glassware by hot air ovens; liquids are autoclaved by moist heat instead.

Why Other Options Are Wrong:

  • IV solution / Plastic IV bags: Use moist heat or aseptic manufacture; dry heat is unsuitable.
  • Rubber gloves: Typically sterilized by EtO or gamma; dry heat degrades elastomers.

Common Pitfalls: Assuming any heat method works for all items; material compatibility is crucial.

Final Answer: Glass pipettes are appropriate for dry heat sterilization.

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