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Denatured alcohol

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Denatured alcohol

Postby biznatch » Mon Jul 07, 2008 9:34 pm

Can denatured alcohol (90% ethanol, 5% methanol and 5% 2-propanol) generally be used in place of 100%/anhydrous ethanol? In QIAGEN kits it specifically says not to use denatured alcohol when making up Buffer PE but what about other things in general? Like fixing cells with 3:1 methanol:ethanol, H&E staining, washing DNA pellets or even making 70% ethanol for cleaning things for tissue culture? If it's still ok to use, should it be treated as 90% when doing calculations?
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Postby biohazard » Tue Jul 08, 2008 10:03 am

Uh, good question. The answer depends on the intended use of alcohol: for cleaning and disinfection, denatured EtOH is just as good, and can be treated like normal, pure ethanol what comes to calculations (those other alcohols are toxic to microbes as well).

For staining, well, I'd just try it out and see if the staining is okay :)

And for anything more sophisticated, I'd avoid using denatured alcohol altogether - after all, pure ethanol shouldn't be that hard to come by.
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Postby biznatch » Tue Jul 08, 2008 2:18 pm

Thank you! It's not that hard to come by (actually we've been using it forever and just decided to switch), but the denatured alcohol is cheaper and there's no regulations on it. E.g. with 100% EtOH we have to keep track of every time we use it to show a record when certain inspectors/safety people come. We'll give the denatured alcohol a try and see what works, unless anyone else has more ideas.
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Postby biohazard » Wed Jul 09, 2008 6:02 am

Heh, that's true: all those regulations make the use of 100% EtOH pretty annoying sometimes.

Despite this, our department uses pure ethanol to make 70% dilution for disinfection purposes. It may be because spraying denatured ethanol on surfaces could cause some degree of toxic fumes (from methanol). Although as far as I know, the exposure for humans from this is next to nothing (or if you spray the laminar flow hood / fume cupboard, there's no exposure). But that aside, denatured alcohol should be as good a disinfectant than 100% ethanol.

Actually, now I think I'll ask about this in our next department meeting, because disinfection is the main reason I need to be fetching new 100% ethanol all the time :P
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