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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: hairul on February 09, 2016, 08:19:25 PM

Title: High Range COD by Colorimeter
Post by: hairul on February 09, 2016, 08:19:25 PM

Hi,

I am new in using DR/980 Hach Colorimeter which have limit at 1650mg/L. I intend to determine COD value in solid sample. Can anyone propose to me the dilution factor?

Thanks.

Title: Re: High Range COD by Colorimeter
Post by: microchips on March 03, 2016, 10:10:53 AM

Hi,

the biggest factor here is what your sample is made of, and how high you expect the COD to be. assuming it's a sludge, i would do at least 50x dilution.

the thing about COD (and BOD too, for that matter) is that sample prep is so time-consuming, it makes sense to do a few dilutions in parallel rather than have to wait and re-run with the next batch.