Why can alcohol sterilize and disinfect? Why is the sterilization effect of pure alcohol not good?

Alcohol can penetrate into the bacteria and cause the proteins that make up the bacteria to coagulate. Therefore, alcohol is commonly used as a disinfectant in medical and health care. Why use 70% 75 alcohol instead of pure alcohol for sterilization?

This is because the higher the alcohol concentration, the stronger the effect on protein coagulation. When a high concentration of alcohol comes into contact with bacteria, it can quickly solidify the surface of the bacterium, forming an envelope, preventing the alcohol from continuing to penetrate into the inside of the bacterium. The cells inside the bacteria are not completely killed.

When the time is right, the cells within the capsule may break through the capsule and come back to life. Therefore, the use of concentrated alcohol cannot achieve the purpose of disinfection and sterilization. If 70% 75 alcohol is used, it can not only coagulate the proteins that make up the bacteria, but also cannot form an envelope, so that the alcohol can continue to penetrate into the inside, and make it completely disinfected and sterilized.

Experiments, if the alcohol concentration is lower than 70, it cannot completely kill bacteria.

It can indeed have a sterilizing effect, because the purity of alcohol is relatively high, and this alcohol can directly kill bacteria, so it can have a sterilizing effect.

Of course, you can use more than 95% of the hotels, so that the effect of alcohol sterilization and disinfection will be better.

Of course, it is enough to use the above hotels, such as the fruits of alcohol bacteria elimination.

It is because alcohol can absorb the water of bacterial proteins, dehydrate and decentralize them, so as to achieve the purpose of killing bacteria.

Only ethanol solutions with concentrations higher than 60% have an elimination effect. Ethanol at a concentration of 75 to 80 percent can kill most bacteria and enveloped viruses in a matter of seconds, but not bacterial spores. Of these, 75% ethanol is the most commonly used concentration and is most widely used in hospital systems, research labs, and other settings that require sterilization.

95% high-concentration ethanol is good for disinfection, but not as good as diluted ethanol, of which 70% to 75% is best.

This is because the high concentration of ethanol causes the proteins on the surface of the bacteria to coagulate and form a hard membrane, thus protecting the bacteria from being permeated by alcohol. At this point, the cells become inactive, but they do not die. So 75% ethanol is a better choice.

The higher the concentration of alcohol, the better, and the higher the concentration, the stronger the disinfection effect. 95%. Of these, 75% ethanol is the most commonly used concentration and is most widely used in hospital systems, research labs, and other settings that require sterilization.

95% high concentration ethanol sterilization. Of these, 75% ethanol is the most commonly used concentration and is most widely used in hospital systems, research labs, and other settings that require sterilization. 95% high-concentration ethanol disinfection High-concentration alcohol rapidly dehydrates the proteins on the surface of bacteria before penetrating into pathogens represented by bacteria.

In order to form a tight protective layer of protein on the surface of the bacteria, preventing further penetration of alcohol.

Some bacteria contain spores with an alcohol content of less than 70%, which is too low to effectively kill bacteria or viruses once they enter the body. However, alcohol above 75% forms a protective film over bacteria or viruses, preventing them from being effectively inactivated. Attention should be paid to alcohol disinfection, because alcohol is volatile and has a low melting point, which can easily pose a fire hazard.

When using alcohol disinfection, it is best to wipe it, avoid spraying, avoid sources and flammable materials, and turn off the power when disinfecting electrical appliances.

Alcohol can denature, coagulate and die of microbial proteins, so as to achieve the effect of sterilization and disinfectionPure alcohol will cause the protein on the surface of microorganisms to coagulate quickly, but form a protective film, which is not easy to kill microorganisms;

It turns out that alcohol disinfection and sterilization mainly uses the strong permeability of diluted alcohol to penetrate into the bacteria, and then coagulates the proteins in the entire bacteria and kills the bacteria. If you disinfect with pure alcohol, the concentration of alcohol is very large, and the protein on the surface of the bacteria will coagulate at once, forming a hard film. This hard film has a protective effect on bacteria, preventing further penetration of alcohol, but it does not achieve the purpose of disinfection and sterilization.

The scientific name of alcohol is ethanol (C2H5OH), which has a strong penetrating power and can drill into the bacteria, causing the bacteria to coagulate (chemically called denaturation), causing the bacteria to lose their activity and die. In the past, people thought that pure alcohol would denature the proteins of bacteria too quickly and strongly, and the proteins would solidify on the surface of the bacteria and form a hard membrane, preventing the alcohol from further penetrating into the bacteria, resulting in the result that pure alcohol could not be disinfected and sterilized. Actually, neither pure alcohol nor pure water alone can denature proteins, and it is only when water and alcohol are present at the same time that the alcohol solution shows the ability to denature proteins.

It turns out that protein is a very complex macromolecular structure, which is bent into a certain geometric shape by a long spiral chain. If the three-dimensional structure of a protein is destroyed and cannot be reduced, it loses its physiological activity. In protein molecules, there are many hydrophobic groups that exist inside the long helical chain, and many hydrophilic groups that are "exposed" to the outside.

Therefore, the periphery of the protein molecule is very "intimate" with water, and it has a certain amount of water solubility and forms colloids. There is a certain attraction between the hydrophobic groups inside the protein and between the hydrophilic groups on the outside, which makes it appear stable and active. To denature proteins, it is necessary to stretch and relax the long chains of protein molecules that are fist and helix, and the key is to destroy the various forces that form fist flexes and helix.

The alcohol molecule has two ends, one end is hydrophobic (-c2h5), which can destroy the attraction between hydrophobic groups inside the protein; One end is hydrophilic (-0h), but it is difficult to break the force of attraction between hydrophilic groups outside the protein. On the other hand, although the water molecule can relax the attraction between the hydrophilic groups of the protein, it cannot destroy the attraction between the hydrophilic groups in its protein even if it burrows inside the bacteria. Therefore, neither pure alcohol nor water is sufficient to denature the protein within the bacteria, and the protein will lose its physiological activity only if alcohol and water coexist while relaxing the various attractions that maintain the geometry of the protein.

Therefore, only a certain concentration of alcohol solution can achieve a good disinfection and sterilization purpose.

This is because pure alcohol has no disinfecting effect and is not very useful.

Because alcohol is too high, it has no sterilizing effect.

Seventy-five percent of alcohol can achieve the effect of sterilization, and 100 percent of it is toxic to the human body.

Alcohol can't be sterilized because it's not that profitable.

As we all know, the concentration of medical alcohol is 75%, and 100% is harmful.

Pure alcohol can also kill sperm, why not, don't believe you try.

Seventy-five percent alcohol can achieve a bactericidal effect, and everyone knows common sense.