Alcohol (ethanol) is one of the most commonly used disinfectants in medicine. It is the most widely used disinfectant. It is soluble in water and has a certain fat solubility. The mechanism by which ethanol sterilizes and kills viruses is that its fat solubility can destroy the biofilm composed of biological phospholipid bimolecules, causing biofilm structure and dysfunction. The higher concentration of ethanol can destroy the "order" of the membrane structure, thereby destroying the function of the membrane, leading to the death of "membrane" microorganisms.
The effectiveness of alcohol in disinfectants and disinfectants depends on the concentration of ethanol. To achieve the effect of killing 99.99% of bacteria, the ethanol content should usually reach more than 60%.
The study found that ethanol solutions with a concentration of more than 60% have a killing effect; when the concentration reaches 75% to 80%, it can kill most bacteria and enveloped viruses in a few seconds, but it is not effective for bacterial spores. Among them, 75% ethanol is the concentration commonly used by people, and it is most widely used in hospital systems, scientific research laboratories and other occasions that require disinfection.
However, 95% of high-concentration ethanol disinfection and sterilization effect, but inferior to dilute ethanol, of which 70% to 75% is best. This is because the high concentration of ethanol will cause the protein on the surface of the bacteria to condense to form a hard film, and the change of direction will protect the bacteria and prevent the further penetration of alcohol. At this point, the cell will become inactive, but will not die. Therefore, 75% ethanol is a more ideal choice.