What kind of electrodes? Stainless steel? Glass? Do you _really_ mean
"sterile"? Or, sanitized?
True sterilization with alcohol is _NOT_ effective. There is a big
difference between sterilization vs. sanitization vs. disinfection. The
difference from a 12 log reduction in count to a 2 log reduction,
1,000,000,000,000 to 100. Each has its own requirements.
Which do you really have to do? This depends on where the electrodes will
be going. If they are going into a human (brain electrodes), you need
de-pyrogenation (anti-endotoxin) as well as sterility by overkill method
or "F sub-o" (12 log reduction of _Clostridium botulinum_ or 6 logs of
_Bacillus stearothermophilus_ spores).
Alcohol only kills gram positive coccus well e.g. _Staphylococcus aureus_.
BUT, not G+ rods (_Bacillus_, _Clostridium_) i.e. not endospores, not
yeast (yeast like to make alcohol and are tolerant of ethanol but less
tolerant of IPA, about 50 times less tolerant according to my studies),
alcohol will also not mold spores. Gram negative are usually killed if
not in too high bioburden. In fact, low bioburnen (<2 logs) is always
advisable.
50-70% IPA is optimum for Gram + coccus. See also the post by
Andreas.Brune at uni-konstanz.de (Andreas Brune), polio vaccine had a problem
in attennuation for a similar reason (alcohol contant was too high and
protected the viruses).
Do you really need sterilization (unlikely)? Use heat if possible, dry
heat 200C for 2 hours or steam 15 PSIG for 15 minutes or "F sub-o" = 15
minutes at the coldest spot in the load (not just the chamber) .
Sterilization depends on both time and temperature.
Fast bunsen burner "flaming" with alcohol will not be hot enough nor long
enough to sterilize, but will probably be all you really need for
sanitization.
Dynamically Optimistic!
Davin C. Enigl
Send Internet e-mail to: enigl at aol.com
Send AOL e-mail to: Enigl
December 20, 1995
8:04 pm
