Talk:Blank (solution)

Move some material from Chemical oxygen demand article

The following material was deleted from the Chemical oxygen demand article because it wasn't really specific to that article. I added back a reference to the article here, and maybe someone knowledgeable can rework the text that was deleted so that it fits here.

Because COD measures the oxygen demand of organic compounds in a sample of water, it is important that no outside organic material be accidentally added to the sample to be measured. To control for this, a so-called blank sample is required in the determination of COD (and BOD -biochemical oxygen demand - for that matter). A blank sample is created by adding all reagents (e.g. acid and oxidizing agent) to a volume of distilled water. COD is measured for both the water and blank samples, and the two are compared. The oxygen demand in the blank sample is subtracted from the COD for the original sample to ensure a true measurement of organic matter.

External links modified

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• Added archive https://web.archive.org/web/20130613220821/http://www.epa.gov/region3/esc/qa/pdf/blanks.pdf to http://www.epa.gov/region3/esc/qa/pdf/blanks.pdf

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