RE: automated IHC - Dab disposal

From:Louise Taylor <>

Hi Hazel,
thanks for your reply to my query. Just a 2 things that need clarification.
Firstly, when you say "working DAB" is this the amount of DAB in the waste
disposal container or the amount of liquid dab as used per run-excluding all
the water used for washing out the machine at the end of a clean cycle ? i.e
a run of 48 slides would use 200ul each = 9600ul, but then would be diluted
by water for the "wash cycle?" am I getting you confused?

Secondly, what volume are you dealing with each day? I get about 10l per
week, and I am concerned that I will end up with huge carboys of pot permang
and sulphuric acid and gently bubbling solutions lying all over the place!
This is getting to be quite a problem!!!

Best regards

-----Original Message-----
From: Horn, Hazel []
Sent: 13 November 2000 09:07
To: 'Louise Taylor'; histonet
Subject: RE: automated IHC - Dab disposal

> Louise,
> This is the procedure approved by our state water department for disposal
> of used DAB waste from our Dako autostainer.   You might need to check
> with your state water department before using this procedure.
	[Horn, Hazel]
	1.   Prepare the following stock solutions:
	      0.2 M Potassium Permanganate (31.6 g KMnO4/liter)
	      2.0 M Sulfuric Acid (112 ml concentrated acid/liter)
	2.  For each 10 ml of working DAB solution, add:
	     5 ml 0.2 M Potassium Permanganate
	     5 ml 2.0 M Sulfuric Acid
	3.  Allow the mixture to stand for at least 10 hours.   This will
allow it
	     to become noncarcinogenic.
	4.  To decolorize the mixture, add powdered ascorbic acid until the
	     color disappears.
	5.  Neutralize  the decolorized mixture with sodium bicarbonate.
	     the neutrality (pH meter, pH paper or dipsticks)
	6.  Discard by pouring down the drain with copious amounts of

	If anyone has a simpler method we would sure love to have it.    By
the way, our water department will not allow us to use the procedure using

	I hope this helps!!!

> I asked this question last week, but due to technical errors received only
> one reply, so I'm asking it again. How do labs using the Dako autostainer
> deal with their DAB waste? Have it collected by a waste company? If so -
> what do they do with it?
> Deal with it in-house? Pour it down the drain?
> Best regards
> Louise Renton
> Research Laboratory
> Department of Anatomical Pathology
> South African Institute for Medical Research
> Johannesburg
> South Africa

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