How to prepare your own pH buffers for pH meter calibration from scratch

This video shows you how to prepare pH 4 and pH 7 buffers for pH meter calibration using readily available low cost raw salts. These buffers have a strength of 0.1M. These are the amounts needed to prepare 250mL of buffer solution:

pH 4
Potassium Citrate 2.63g
Citric acid monohydrate 3.45g
(if using anhydrous citric acid, use 3.15g)

pH 7
Potassium Citrate 7.14g
Citric acid monohydrate 0.35g
(if using anhydrous citric acid, use 0.32g)

(Please notice that the Amazon links below are affiliate referral links. This means that if you click on them I may receive a commission from purchases. There is no additional cost to you, but it helps me to keep posting content for free.)

Class A Volumetric Flask (250mL)
Beaker set
Scale
Citric Acid Monohydrate
Citric Acid (anhydrous)
Potassium Citrate
Silicon ice cube trays (similar, but not exact ones shown in video)

[jamesmelendez]

Impeccable style, full of accuracy, and very thorough! A great way to remind oneself, "don't be a savage!"

[davidnewton]

So I just came across your channel and I am super glad I did. Looking at your list of videos I'm sure I'll be binge watching and attempting to play chemist and save some cash on all the commercial buffer solutions.

On this video I would have liked to see you test a commercial solution and your solution as proof of concept. Not that I don't trust you and all but I'm big on validation.

One thing I didn't see in your videos was the KCl "storage solution" that is always recommended for storing our ph probes. I mean Im no chemist but Im guessing there is more to it than just buying some potassium chloride solution and dropping my probe in. Just a thought.

[davidedwards]

Thank you for the video! I'd like to add, when trying to weigh hundredths of a gram and you think its not adding any mass, try tapping the container and let the scale settle. It'll tell you where you're at and avoid over shooting sometimes. Hope that helps.

[jand]

Very good material. I appreciate your efforts. I have an important clue. At 7:21 when you transfer quantitatively from a beaker to a volumetric flask - you should use a small glass or plastic funnel. By pouring directly from the beaker to flask, you risk spilling beyond that narrow neck of the flask. Even the loss of one drop makes a difference. You then lose some of the substance, and the acid-base balance will not be maintained. Therefore, the pH will not be as assumed by the calculations, and precise weighing.

[Blergoz]

Thank you for all the amazing information you are providing.

[animerecaps]

useful videos and tutorials. thank you very much for sharing your knowledge. ❤️ from philippines

[nicoherrerai]

New subscriber, extremely helpful, thaaaanks man, thanks for taking the time

[normantaffefiny]

Hi His i love your videos, i wonder if u have time to make a video on chelating agents in hydroponics

[catherinelagamon]

Hello. Do you have any idea how to make it colorful? Like different colors for pH =4, 7 and 10?

[ivanpap]

I do always share your useful and interesting videos, I'm mot a savage LOL tank you very much for yours teachings

[canyonlewis]

Hello David, Always a pleasure to follow your thorough content.
Is there a major difference between pH UP and pH DOWN solutions to this pH buffer solution?
If so, may I make a video request to enlighten us on the differences and how to mix your own pH UP and pH DOWN solutions?

[ammarahmed]

Thank you Sir. please share calculations

[PoiKiaMau]

Hi Daniel, Is it possible to add Sodium Benzoate to this mix or will it alter the pH of the formula? Thank you again for sharing your knowledge.

[zaryabkhan]

Hey David I am new here
Very informative video
Can i replace potassium citrate by sodium citrate.
And how much sodium citrate should be needed to make a solution of ph 4 and 7

[BinladensCloan]

Awesome video. I can't find potassium citrate anywhere near me, I live in South Africa I've tried looking online but nothing. Is there another name for it in the food industry?

[illiath]

very good video! But i have a question. There are different potassium citrate out there.. Some contain 35%, some 36% potassium. Does this make any difference? Thanks!

[ShopperPlug]

This is really useful always wanted to know how to make my own pH buffers. Would like to know the theory of pH buffers and how it's calculated also what is the stable shelf life of the solution? I'm curious why does the ready made commercial pH buffers expire? Does the solid chemicals salts such has potassium citrate and Citric acid monohydrate expire, can I keep these powered chemicals viable for a long time such as 10+ years to keep on making pH buffers? Thanks.

[eyhd]

Hi
Please do the calculations and tell us how you understand the amounts??
Is it Henderson equation or what??
Thanks BTW.

[shalundike]

Hello David, new subscriber here. I find it hard to get potassium citrate, what can I substitute it with??

[CannabinaTV]

Hey Dr. Is there anyway to stabilize the final solution? For long term storage. can you teach us how to use phosphorous acid to buffer and some raise the pH.