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Buffering Question
I need to make some pet products (Shampoo, ear cleanser and coat conditioner) that contains 2% acetic acid and 2% glycolic acid. Can some suggest what to use and how to go about buffering this to a pH of about 5.9? Thank you.
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11 Replies
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Having formulated and manufactured pet products some years ago, my immediate questions are why the 2% acetic acid and 2% glycolic acid? And why a pH of 5.9?
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I am a contract manufacturer and the only answer I can give you is because that is what the customer requested. Sorry I don’t have any other info to reply with. They did have boric acid in their products but some of them get exported to the EU and they said EU is cracking down on use of boric acid in products. I am trying to find out of that is for only human products or all products.
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Hi, i just found this case in my formulation. I used to adjust pH around 6-7, bc one of raw material(cooper peptide) is very sensitive to acidic condition. I tried to add NaOH solution to adjust the pH until that range, but overnight the pH decrease around 4-5 and the color changes to yellowish green.
Can you suggest me what material should i add to the bulk to maintain the pH still in 6-7 range?
Thank you.
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Did you adjust the pH BEFORE adding the peptides? Because if you adjusted the pH it can’t change unless something is interacting in the formula. Since you’ve got green color I suspect it is oxidized copper. You need to check what other incompatible ingredients you have
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Yes, i adjust the pH before adding copper peptide. I really confuse why the pH still decrease.
I use the ferment fruit extract as active and capryin the formula. Maybe it suspected that cause
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@Kireisha what chelate and what preservative are you using? Is there something more than ‘caprylhydroxamic acid’ in the mixture?
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I don’t use chelating agent. I use spectrastat PHL as preservative
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Yes, i adjust the pH before adding copper peptide. I really confuse why the pH still decrease.
I use the ferment fruit extract as active and caprylhydroxamic acid mixture as preservative the formula. Maybe it suspected that cause the pH decrease?
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You might have just made a buffer yourself. If you managed to neutralize half of you acetic acid for instance, then you might have created a 4.5 pH buffer. The frst reading you had at around 6 is the free sodium hydroxide, because your system didn’t reach equilibrium. Working with that amount of acids is very hard indeed. I’d just theoretically find the amount of NaOH to make a pH 6 buffer, and use that as a starting point…but that means you’ll have to consume quite some NaOH. As a side note, your preservative actually has a chelant (the organic acid, but it’s just a very poor one), and In fact, more than a preservative, it’s a booster. Please use a more robust preservative system. Or get rid of the peptide (not doing anything really) and embrace benefit yourself from the low pH of your system (4.5 is OK for your type of product, which would make it possible to work with many preservatives).
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As mentioned… Caprylhydroxamic Acid, has some chelating activity….so gonna eat up your copper. In my mind, that is the only good thing about Caprylhydroxamic Acid….is the chelating aspect. Every other aspect is intensely negative.
Lose the peptide, or keep it at .001% for marketing material.
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Is it possible to use the buffering system like sodium citrate? Just to keep the pH above 5.5, then it won’t turn to yellowish green appearance ?
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