Question

why we not use higher concentration of isopropyl alcohol (90%+) in the laboratory for sterilization?​

Answer 1

Answer:

Isopropyl alcohol, particularly in solutions between 60% and 90% alcohol with 10 – 40% purified water, is rapidly antimicrobial against bacteria, fungi, and viruses. ... Notably, higher concentrations of alcohol don't generate more desirable bactericidal, virucidal, or fungicidal properties.

Answer 2

Answer:

To put it simply, higher concentrations cause an external injury that forms a protective wall and shields the organism. Furthermore, 99% isopropanol evaporates very quickly which does not allow it to penetrate cell walls and kill bacteria, and therefore isn't as good for disinfecting surfaces.