An alcohol gel, also known as a hand sanitizer, is a gel used in hospitals as an alternative to hand washing with soap and water. Isopropanol and/or ethanol are the most commonly used alcohols.

Alcohol concentration must be above 60% for alcohol gel to be effective in killing microbes. Researchers at East Tennessee State University recently found that products with alcohol concentrations as low as 40% are available in American stores.

Alcohol gel can be used quite like a mild napalm. If one applies it liberally in any shape, it can be lit with fire to produce a low blue flame. This is due to alcohol producing a blue flame when lit. Some hand sanitizer gels may not produce this effect due to a high concentration of water or moisturizing agents.

Not all pathogens are equally susceptible. Certain bacteria, especially the spore-forming gram positives (e.g. Clostridium difficile) are relatively immune and remain contagious.

There are rumors that use of the gel over a period of time will cause the gel to lose its effect as bacteria becomes immune. This, however, is only a rumor. The alcohol content is too great for bacteria and microorganisms to become immune in less than about 15 to 20 years.

Sources

• http://www.colostate.edu/Orgs/safefood/NEWSLTR/v8n3s06.html
• Reynolds SA, Levy F, Walker ES. 2006. Hand sanitizer alert (letter). Emerging Infectious Diseases (CDC publication).

gels | Medical hygiene