23 replies to this topic

[chimaera]

gt_ameya, on 24 November 2010 - 11:23 PM, said:

After much search, I ended up troubling my supervisor, who was kind enough to give me the title and author of the paper. As it turns out, it was published in 1950 (before my supervisor was born) and is called THE RELATIONSHIP OF CONCENTRATION AND GERMICIDAL EFFICIENCY OF ETHYL ALCOHOL
Harry E. Morton.

This paper describes ethanol tested on bacterial pellets, which means it was tested on wet cells. However, it has been shown that for dry surfaces absolute alcohol might not work as a disinfectant.
Most likely that is why a water-alcohol solution is used in labs.

[hobglobin]

adrian kohsf, on 25 November 2010 - 12:36 AM, said:

Hi hobglobin, I too uses 80%~85% alcohol on bench. Is there any way that I can get the chapter in PDF? my library doesn't have it...
Thanks.

From the book? Sorry, I don't have it, I use google book, that's enough for me  

[pito]

gebirgsziege, on 25 November 2010 - 12:06 AM, said:

gt_ameya, on 24 November 2010 - 11:23 PM, said:

But I can't access it from here.... and it will be nice, if some one sends it back to me.... I promise to treasure it this time....  

see your pm!

If possible: can you send a copy to me too?

thanks

[Ameya P]

pito, on 27 November 2010 - 10:54 AM, said:

gebirgsziege, on 25 November 2010 - 12:06 AM, said:

gt_ameya, on 24 November 2010 - 11:23 PM, said:

But I can't access it from here.... and it will be nice, if some one sends it back to me.... I promise to treasure it this time....  

see your pm!

If possible: can you send a copy to me too?

thanks

see your pm...

[josse]

I have another question regarding the ethanol problem: should you always dilute the ethanol in demineralised water or even deionised? Or can you simply use tap water?

thanks

[gebirgsziege]

We usually use demineralised water, but I think tap water will be fine as well.....

[pito]

gebirgsziege, on 29 November 2010 - 03:03 AM, said:

We usually use demineralised water, but I think tap water will be fine as well.....

I am not so sure about that...

Tap water contains salts and isnt it possible you can get a precipitation reaction and also withdraw water from the mixture?

(or something like that.. my chemistry is not that good anymore )

[gebirgsziege]

I was thinking about the minerals in the water as well, but think that this does not influence the mode of action, but if anybody knows the difference I would be happy to know.

[hobglobin]

Depending if you have "hard" water or not you'll have a more or less strong precipitation of the minerals, as they're not very soluble in ethanol (especially polyvalent ions). For sprayers it might be bad (blocking), but if the minerals are gone, there should be no influence on the action of the alcohol itself.