pH Buffers

[bigmack]

Hi Labbies .
I've just realized all our Sparkvue pH probes are well out of calibration.
I have also realized that we have no pH4 buffer solution .
I have also just realized that Buffer solution has a limited shelf life 12-18 months unopened and less than 3 months when opened .

At old school we had buffer Tables .....dozens and dozens of them .So I never bought buffer solution and made up fresh with tablets when needed.

It seems a waste of money buying 500ml bottles of Buffer when it is likely out of date by the next time it's needed .

I see Haines sell tablets , about $20-25 for 10 .thats over $75 for all three with freight and GST

I see Westlab sell buffer solution .Best price around .

Does anybody make up Buffer Solution as per Prima's recipe here ?
viewtopic.php?p=44189#p44189

What do you all do ?

[RosalieL]

Do you have the other buffer solutions? pH 7 and 10? Can you use those to do a 2 point calibration and hold off ordering the tablets for when you're placing another order? Sorry I haven't tried the "home made" ones you've linked. I don't actually know what my plan is at this school as we have the solutions here and I'm hoping they're still good when we need them! My old school we used to get the buffer tablets as well because they were used so infrequently.

[RosalieL]

Depending on how much time you have up your sleeve, Perth Scientific have them cheaper but postage may be a killer.

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[bigmack]

Thanks Rosalie.
That's a great price . Haven't checked freight yet , but surely can't be more than $25 Haines wanted .

[bigmack]

OK I just did it .$33 flat fee freight.
$77.55 for 3x Buffer tablets (4,7,10) and Freight .

[Merilyn1]

Sometimes you just have to do it!