Author Topic: pH Buffer Solutions - Shelf Life?  (Read 421 times)

Offline Don

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pH Buffer Solutions - Shelf Life?
« on: September 22, 2013, 08:52:58 PM »
Just bought my first pH meter and noticed it came with foil sachets of buffer solutions for calibration. This got me thinking about whether to purchase these single-use packages or the larger bottles of solution. The bottles are more economical as long as the solution lasts long between cheese makings. I'm a newbie who makes cheese about once every month. So my question for the more experienced members is whether to purchase the single use foil packages of buffer solution or the 250 or 500 ml bottles. Just don't know how long the shelf life is for the bottled solutions.


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Offline linuxboy

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Re: pH Buffer Solutions - Shelf Life?
« Reply #1 on: September 22, 2013, 08:57:12 PM »
Unless you are doing analytical work or something that requires an extraordinary precision degree, so long as you don't dip the probe into the bottle, the solutions don't really go bad. Maybe eventually, but it's never happened to me in ~20 years.
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Offline Tomer1

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Re: pH Buffer Solutions - Shelf Life?
« Reply #2 on: September 23, 2013, 07:22:55 AM »
as long as you dont double dip, rinse with distilled water and dry the probe between solutions they are good for years maybe. 
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Offline Don

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Re: pH Buffer Solutions - Shelf Life?
« Reply #3 on: September 23, 2013, 08:19:13 PM »
Thanks Linuxboy and Tomer1 for the advise. (Would you believe I spoke to a chemist today that told me the exact same thing!) 

Offline linuxboy

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Re: pH Buffer Solutions - Shelf Life?
« Reply #4 on: September 23, 2013, 08:33:16 PM »
Quote
Would you believe I spoke to a chemist today
You mean you've now talked to two ;) :)
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Offline UVM-cheese-LAB

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Re: pH Buffer Solutions - Shelf Life?
« Reply #5 on: October 20, 2013, 06:30:03 PM »
Dear Don,
I second and third the opinions of the other two chemists.  If you do choose to use single use sachets, be sure to dissolve them in deionized water, which can be purchased from a pharmacy.  Using tap water may throw off your calibration.

Also, rinsing between calibration points with deionized (or distilled) water, as Tomer1 pointed out, will also help with your calibration accuracy.

The following link is for a wash bottle which can be filled with deionized water and used to rinse your electrode between calibrations.

http://www.amazon.com/Wash-Bottle-Widemouthed-Distilled-Water/dp/B005MIPSYI

Happy cheesemaking,

UVM-cheese-LAB