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Topic: Sodium Acetate Buffer  (Read 666 times)

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Offline znaes97

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Sodium Acetate Buffer
« on: December 01, 2022, 11:19:07 AM »
Hey everybody,
I have a procedure to check for the presence of chlorine in waste water. The procedure says to use a sodium acetate buffer. Does it have to be sodium acetate or can we use something else like an ammonium acetate buffer? Any help is greatly appreciated.

Offline Hunter2

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Re: Sodium Acetate Buffer
« Reply #1 on: December 01, 2022, 12:01:16 PM »
A sodium acetate buffer contains the equal moles of sodium acetate and acetic acid. The concentration  and the to achieve pH you have to know.  Calculation with Hendersson Hasselbalch equation.

Offline znaes97

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Re: Sodium Acetate Buffer
« Reply #2 on: December 01, 2022, 12:06:00 PM »
The procedure doesn't say anything about concentration. It just says "moisten a strip of potassium iodide starch paper with the sodium acetate buffer." A little more detail about the procedure, it is a two part check for cyanide in waste water. The first check is for chlorine and the second is for sulfide. Both checks require the sodium acetate buffer.

Offline Hunter2

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Re: Sodium Acetate Buffer
« Reply #3 on: December 01, 2022, 12:09:44 PM »
I would suggest to use a 0,1 M buffer. 0,05 M CH3COONa  and 0,05 M CH3COOH

Offline Borek

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Re: Sodium Acetate Buffer
« Reply #4 on: December 01, 2022, 12:17:30 PM »
Procedure as worded is ambiguous - acetate buffer means a buffer made by mixing acetic acid with some acetate (typically sodium), but what are concentrations of these and what is their ratio is in no way obvious. Acetate buffer typically means something between pH 4 and 5.5, exact value can be important, or it can be not, depends on the reaction details.

Buffer has to be selected carefully, so that it doesn't interfere with the detection reaction. Say, if you detect chlorides with Ag+, any ion reacting with Ag+ will give you a false positive. Acetate buffer is a common selection in such cases.
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