3 ms·
> They're not able to survive 100% alcohol (or close to 100%) IIRC, there's something of a peak in the effectiveness curve below the close-to 100% [1] point fo
by mmt 8y ago
> They're not able to survive 100% alcohol (or close to 100%)
IIRC, there's something of a peak in the effectiveness curve below the close-to 100% [1] point for ethanol, having something to do with too high a concentration not actually penetrating cell membranes fast enough when there isn't enough water in solution already. It's been a while since I read up on it. The papers are out there, for the curious.
That said, I also recall the European standard of 85% (w/w?) being far better as a disinfectant, as supported by the evidence, than the US minimum of 62% w/w (or 70% v/v). Perhaps instead of a ban, merely increasing the minimum percentage to something that doesn't encourage resistance would be enough.
[1] 96.5% or thereabouts is the highest distillation concentration, above which it would be hygroscopic and come down to that if left open to air.
- Scoundreller 8y agoThanks, that makes me feel better about buying hand sanitizer and adding 99% rubbing alcohol once it’s half gone because i’m cheap :)
- mmt 8y agoThat was actually another detail I discovere, although with much less data behind it, that mixtures of ethanol and isopropanol [1] could be more effective than just one alone. Mixing the two works well for liquid formulations, where the dispenser is a fine mist sprayer, but I'd be concerned that anything gelled or with additives for a foaming dispenser might not mix evenly enough. [1] The usual alcohol in "rubbing alcohol" and, of course, for the previously-mentioned reason, ethanol is excluded if it's 99%