What type of alcohol and concentration is required for this test method?

The test method specified requires isopropyl alcohol at a concentration of 70% by volume. Isopropyl alcohol, also known as isopropanol, is commonly used in laboratory settings for its effectiveness as a disinfectant and solvent. The 70% concentration is particularly important because it has been shown to be optimal for antimicrobial activity, as it allows sufficient contact time for the alcohol to penetrate the cell walls of microorganisms, leading to effective disinfection.

Using a higher or lower concentration may impact the efficacy of the alcohol. For example, a concentration greater than 70% may evaporate too quickly to provide adequate contact time with the surface being disinfected, while a lower concentration might not be potent enough to effectively kill pathogens. Thus, the specific requirement for isopropyl alcohol at 70% by volume ensures that the method follows best practices for producing reliable and valid results.