Ask A Scientist© Molecular Biology Archive

name         Wolf Wolfstar
status       educator
age          40s
Question -   Is a 1:100 dilution of 5.25%
sodium hypochlorite and  water a good broad spectrum
disenfectant that can be used in commercial  settings?


First of all a few definitions: Antiseptics are microbicidal agents 
harmless enough to be applied to the skin and mucous membrane; should not 
be taken internaslly.  Examples: mercurials, silver nitrate, iodine 
solution, alcohols, detergents.

Disinfectants are agents that kill microorganisms, but not necessarily 
their spores,not safe for application to living tissues; they are used on 
inanimate objects such as tables, floors, utensils, etc. Examples:
chlorine, hypochlorites, chlorine compounds, lye, copper sulfate, 
quaternary ammonium compounds.

Sodium hypochlorite is the most widely used antimicrobial active chlorine 
compound in chemical
disinfection.

The concentration you mention, 0.05%, corresponds to 0.5 g/l. This 
concentration is sufficient for
bactericidal action, but the time required depends on the concentration.

As far as I know hypochlorite is commercially available for disinfectant 
purposes. It is frequently
used in dentistry. It is not applied as an antiseptic (to desinfect skin) 
because it is not harmless.

Trudy Wassenaar
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.0525 % sounds a little weak to me.  I know weak bleach solutions are good
disinfectants but I am not sure of the concentration.  It will probably be
in a good microbiology text book.

pf
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Sodium hypochlorite is not very stable in the presence of metal ions
and/or light 1:100 sounds rather dilute to me. Although I don't have any
data, I'd estimate one would want about a 1% solution.

Vince Calder
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