From: "STRAUGHN, John" <JSTRAUGHN**At_Symbol_Here**FPM.WISC.EDU>
Subject: Re: [DCHAS-L] Acidified bleach - dilution question
Date: Tue, 27 Jan 2015 20:39:49 +0000
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: 1B6A9D383A771846BE7E63C1D8758E2F2B8E5752**At_Symbol_Here**

Bleach is simply chlorine gas dissolved into alkaline water; it produces chloride ion and hypochlorite ion, ClO-, along with the sodium ions already present. Adding nearly any acid, even carbon dioxide, will protonate the hypochlorite ion to being unstable hypochlorous acid, HOCl, which reacts with chloride to form chlorine gas. Mixing vinegar, 6% acetic acid (1 molar) and the usual bleach, at 0.75 molar, will too rapidly give you back your chlorine. With one or the other diluted first before mixing to active form is a better way to do things.

I would have 9 parts of 10% bleach, it lasts longer diluted, in the larger chamber and the straight vinegar in the smaller 1 part chamber.


From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of Yanchisin, Mark
Sent: Tuesday, January 27, 2015 1:59 PM
Subject: [DCHAS-L] Acidified bleach - dilution question


I was asked the below from a researcher about the use of acidified bleach to inactivate pathogens..  Anyone used this technique or the spray bottles?  Thanks in advance 


Here is the issue:

I want to use acidified 10% bleach as this is much more effective and has a shorter required contact time for the pathogens we are working with.

The recommendation from DOH and CDC is 1 part bleach 8 parts water and 1 part vinegar.

Adding the vinegar directly to the bleach will change the pH so quickly that the chlorine will ionize and release chlorine into the air so the recommendation is to first dilute the bleach with the water and then add the vinegar.

Here is my issue: we use the sprayers that dilute the bleach with water on the spot.  Pull the trigger and it takes 1 part bleach from one holding chamber and 9 parts water from the other holding chamber in the sprayer. Can I put 10% vinegar in the water holding chamber and achieve the same effect without having that ionizing problem? Essentially diluting the vinegar first and then adding the bleach?

I’m no chemist, so maybe y’all know someone that can answer this question for me.


Mark Yanchisin

Coordinator for Clinical and Laboratory Safety Programs

Environmental Health and Safety

University of Florida

POB  112190 Bldg 179 Newell Dr.

Gainesville, Fl  32611-2190

O- 352-392-1591

F- 352-392-3647



“Just because you are in compliance doesn’t mean you are out of danger.”  Mike Rowe



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