Which of the following is not classified as a disinfectant?

The classification of disinfectants is based on their efficacy in killing or inactivating microbes, including bacteria, viruses, and fungi. In this context, 70% alcohol is actually a well-known disinfectant commonly used in healthcare settings for its ability to effectively reduce or eliminate microbial populations, particularly on skin and surfaces.

The correct answer highlights that 70% alcohol is indeed a disinfectant. Other options like phenol, quaternary ammonium compounds, and glutaraldehyde also serve as effective disinfectants, each with unique properties and applications. For example, phenol has historically been used for its antimicrobial properties, quaternary ammonium is favored for its effectiveness against a range of microorganisms, and glutaraldehyde is utilized for its exceptional ability to sterilize equipment.

In summary, the proper classification of 70% alcohol as a disinfectant helps reinforce the understanding of how various chemical agents are used to control infections and maintain hygiene in clinical and laboratory settings.