[Histonet] Formalin filtering, reuse, expiration date questions

[WILLIAM DESALVO]

I have used the Creative Waste Systems, Alcohol and Formalin for 4+ yrs. and like them very much. The process is simple, the filtered solution is quickly tested and used. There is no distillation of the solution, only removal of elements by the slurry to clean the reagent.
 
We reuse alcohol and formalin for >6 months, adding new solution to adjust concentration. You use a hydrometer for the alcohol solution and there is a pH and formaldehyde concentration test for the 10% NBF. You will perform a validation study comparing the filtered/tested to new solution. Keep the documentation to show your licensing agencies. Re-validate if you change the process.
 
You will follow CAP rules for validating the use of the solution in your process. Label the secondary container that contains tested and filtered solution, according to your validation process. You will continue to test and label as you fill you secondary container.
 
To determine the concentration, you simply use a hydrometer and graduated cylinder.  

William DeSalvo, B.S., HTL(ASCP)



 
> From: Timothy.Morken <@t> ucsfmedctr.org
> To: histonet <@t> lists.utsouthwestern.edu
> Date: Tue, 10 May 2011 12:55:15 -0700
> Subject: [Histonet] Formalin filtering, reuse, expiration date questions
> 
> 
> For those using formalin filtering to recycle formalin (i.e. Creative Waste Solutions formalin filtering unit or other methods), how have you liked it?
> 
> How many times do you reuse the formalin (and how do you tell?!)
> 
> How do you handle an expiration date for the filtered formalin?
> 
> For those using the Creative Waste unit, how well does the assay work for determining concentration?
> 
> Thanks for any and all info!!
> 
> Tim Morken
> Supervisor, Histology, IPOX
> UC San Francisco Medical Center
> 
> 
> 
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