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BUFFERS …
Hello dear members😀,
I went through hundreds of posts/comments here, and I do want to express my gratitude towards @Perry44 for creating this forum, and towards all the members who shared their knowledge for free and posted useful links: @PhilGeis , @Pharma , @Graillotion , @chemicalmatt , @MarkBroussard , and many more.
I am an economist (wish I was a chemist), and I do want to become a better formulator- right now, I’m trying to work my way through the buffers, so please bear with my probably-silly questions.
I’ve found a table on Sigma Aldrich’s website, and regarding citric acid/sodium citrate buffer, my take is: if I dissolve 21g of citric acid in 100 ml of distilled water, and separately 29.4g of sodium citrate in 100ml distilled water, then I will have a 0.1M citric acid solution (A), and a 0.1M sodium citrate solution(B).
According to the same table, for a pH 5 buffer (just as an example), I should make a solution (C) of 35 ml A plus 65 ml B.
Questions, please:
Is all of the above correct? Can be applied to emulsions and water based (toners, serums) products alike?
If yes, how much of the C solution should one add, and at what stage in the process?
Thank you for your help.
PS- home formulator, for now
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This discussion was modified 4 months, 2 weeks ago by
Aniela.
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This discussion was modified 4 months, 2 weeks ago by
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6 Replies
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Your understanding is correct.
Also, sure the buffer can be used in both emulsions and water-based products like toners and serums.
As for the amount to add and the timing:
- Quantity: The specific amount of Solution C to add will depend on your overall formulation and desired pH. Typically, you should start with small increments and measure the pH until you reach your target.
- Stage in the process: It is usually best to add the buffer solution during the aqueous phase preparation, before combining with the oil phase in emulsions or before adding any active ingredients in water-based products. This ensures a stable pH throughout the formulation process.
In truth, I don’t really understand the focus on “buffer systems”. It’s not really a thing that is given much attention in professional formulating.
How did you get interested in it?
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Thank you for your answer, @Perry44
Good question🤔 I’d say, because I’m not a chemist, I’m more scared, as I am not aware beforehand of the possible unwanted interactions/reactions in my products- therefore I try to “cover all bases”.
I was not aware that “It’s not really a thing that is given much attention in professional formulating.” so thank you for highlighting this.
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<font style=”vertical-align: inherit;”><font style=”vertical-align: inherit;”><font style=”vertical-align: inherit;”><font style=”vertical-align: inherit;”>Hi Aniela, I’m new to buffers and I have my doubts, but I’ll share the following with you. </font></font></font></font>
<font style=”vertical-align: inherit;”><font style=”vertical-align: inherit;”><font style=”vertical-align: inherit;”><font style=”vertical-align: inherit;”>At the beginning I did pH tests with 1.96 g of sodium citrate in 90 ml of water and 0.22 g of citric acid diluted in 10 ml of water, adding one ml of citric acid to the 90 ml of sodium citrate. </font></font></font></font>
<font style=”vertical-align: inherit;”><font style=”vertical-align: inherit;”><font style=”vertical-align: inherit;”><font style=”vertical-align: inherit;”>It could be a good way for you to test your aqueous phase. </font></font></font></font>
<font style=”vertical-align: inherit;”><font style=”vertical-align: inherit;”><font style=”vertical-align: inherit;”><font style=”vertical-align: inherit;”>It will depend on your formula, if you already have a high pH due to, for example, anionic surfactants, using the mixture seems unnecessary and just using an acid would be enough. </font></font></font></font>
<font style=”vertical-align: inherit;”><font style=”vertical-align: inherit;”><font style=”vertical-align: inherit;”><font style=”vertical-align: inherit;”>I don’t buffer all the products and the pH can take a little time to stabilize so my tests were first barely mixing, then 12 hrs and then several days.</font></font></font></font>
I hope I’m helping you 🙂
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(Sorry, I don’t know what happened in the previous post)!
Hi Aniela, I’m new to buffers and I have my doubts, but I’ll share the following with you.
At the beginning I did pH tests with 1.96 g of sodium citrate in 90 ml water and 0.22 g of citric acid diluted in 10 ml water, adding one ml of citric acid to the 90 ml solution of sodium citrate. It could be a good way for you to test your aqueous phase.
It will depend on your formula, if you already have a high pH due to, for example, anionic surfactants, using the mixture seems unnecessary and just using an acid would be enough.
I don’t buffer all the products and the pH can take a little time to stabilize so my tests were first barely mixing, then 12 hrs and then several days.
🙂
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The previous one is from The X Files😉 (too young?)
Thank you @nkpalaci for taking your time and sharing your experience.
It’s true, not every product needs a buffer. I’ll come back on this subject when in doubt about a specific formula.
PS -I hope your “gray-hair-growing” emulsion is on the right track. Best of luck🙂
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Good question. Why we on the subject does anyone have a formula for KCL Storage solution? So far what I have found is 22.37 grams of KCL (potassium chloride) and add it to 100 mL of distilled water.
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