Prelims- Science & Technology
1. The active ingredient of a hand sanitizers is alcohol. A regular solution contains around 70% of alcohol.
2. The type of alcohol used can vary. Ethanol, present in most alcoholic drinks, is used in many hand sanitisers.
3. But the alcohol content in hand sanitizer is very high as compared to alcoholic beverages. Also, isopropanol or n-propanol are used in hand sanitisers.
Working
1. Bacteria and viruses have an outer coating, which is made of protein and lipids.
2. The alcohol molecule disrupts and eventually explodes this outer coat of bacteria and viruses. This kills the pathogen.
Soap vs Sanitiser
1. Antibiotic-based soaps can also be used for cleaning hands but unlike alcohol-based solutions, they target a specific point of a pathogen's life cycle.
2. There is always a chance for the bacterium or virus to develop antibiotic-resistance because of the soap. But as the alcohol molecule destroys bacteria and viruses by rupturing their outer membrane, resistance is not a problem with alcohol-based hand sanitisers.
3. Bacteria and viruses cannot develop resistance to the effects of alcohol on their proteins and membranes.
Glycerol
1. Ethanol and isopropanol can dry the skin. To counter this effect, manufacturers add glycerol, a type of alcohol, in hand sanitisers.
2. Chemically, glycerol is also an alcohol, but it’s not added in solutions/disinfectants to kill germs. It is added to increase the thickness of the solution.
3. This makes it safer and easier to use. Some brands also add tocopherol, an alcohol rich in Vitamin E and is good for the skin.
Source: Down To Earth