Okay, let's tackle this question about glutaraldehyde. The user provided the question but didn't fill in the options, so I need to figure out the correct answer based on my knowledge. The question is asking which of the following is NOT a use for glutaraldehyde.

First, I should recall what glutaraldehyde is used for. Glutaraldehyde is a chemical used primarily as a disinfectant and sterilizing agent. It's effective against a wide range of microorganisms, including bacteria, viruses, and fungi. It's commonly used in healthcare settings for high-level disinfection of medical instruments. It's also used in the preservation of biological tissues and in histology for fixing specimens.

Now, the options are missing, but I need to think about possible uses and which one might be incorrect. Common correct uses would include: sterilization of endoscopes, preservation of tissues, disinfecting surfaces, and maybe even in some industrial applications. An incorrect use might be something like a topical antiseptic on skin, because glutaraldehyde is irritating and not used directly on skin. Alternatively, it's not used as a general anesthetic or something unrelated like that.

Assuming the options include something like "preservation of biological specimens," "disinfection of endoscopes," "surface disinfectant," and maybe "topical antiseptic," the correct answer would be the topical antiseptic because glutaraldehyde is not used on skin due to its corrosive nature.

So the core concept here is the use of glutaraldehyde in medical and industrial settings as a disinfectant and preservative. The correct answer would be the option that states a use that's not typical, like topical application. The incorrect options would be the actual uses. The clinical pearl is that glutaraldehyde is a high-level disinfectant, not for skin use.

**Core Concept**
Glutaraldehyde is a high-level disinfectant and sterilizing agent used in healthcare for non-porous medical equipment and tissue preservation. It acts by alkylating microbial proteins and nucleic acids, rendering them inactive.

**Why the Correct Answer is Right**
The question asks for an **exception** to glutaraldehyde’s uses. Glutaraldehyde is **not used as a topical antiseptic** due to its cytotoxicity and irritant properties. It is instead reserved for immersion disinfection of endoscopes, surgical instruments, and preservation of biological specimens (e.g., formaldehyde is preferred for skin applications). Its mechanism involves cross-linking proteins, making it unsuitable for direct contact with living tissues.

**Why Each Wrong Option is Incorrect**
**Option A:** *If "disinfection of endoscopes" is listed:* Correct use. Glutaraldehyde is a standard high-level disinfectant for flexible endoscopes.
**Option B:** *If "tissue preservation" is listed:* Correct use. It fixes tissues by cross-linking proteins, widely used in histology and embalming.
**Option C:** *If "surface disinfectant" is listed:* Correct use. It is applied to non-porous surfaces in healthcare settings for sterilization.
**Option D:** *If "topical antiseptic" is listed:* **Incorrect** (this would be the correct answer to the question). Glutaraldehyde is not used on

✓ Correct Answer: B. Thermometer