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Tips for formulating with Copper PCA?
Hi all! I am struggling to introduce Copper PCA to my formula. No matter what I do and what suggestion I follow (4-6 pH, no natural organic compounds like extracts, no EDTA because it precipitates etc) the solution from blue turns to green. As I understand copper oxidizes and gives the green color instead of blue.
This happens even for the plain water+Copper PCA solution (so my actual formula doesn’t really matter). How does companies make it stable? Any deas?
Thanks in advance!
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10 Replies
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hmm for me it sounds like a uv Indicated Reaction. Oxidative is possible. Does it happen in the Dark as well?
Maybe you can add something that absorbs that out of the formulation. Ethylhexyl Methoxycinnamate might help.
I think because of the coloration to green it sounds like you have a lot of Ion reaction with the copper. what kind of water are you using are you adding other ingredients that have a bigger load of Iones like Xantan for example?
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Does it happen in the Dark as well?
Yes
what kind of water are you using
Bottled distilled water from one of suppliers
adding other ingredients that have a bigger load of iones like Xantan for example?
Indeed, in one formula I add a bit of Xanthan. But the green reaction happens even in pure water.
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Does it happen immediately upon dissolving when mixing in plain water?
Aqueous copper ions form colourful complex ions with anions. Cu2+ and Cl- famously make a green solution.
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It happens after a few weeks. Of course the process is gradual, but I notice the huge difference in color after few weeks
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Maybe some water soluble antioxidant help.
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Manufacturers of Copper PCA mention it as being an antioxidant. Color change can be linked in this case to an oxidation process. If that’s the case, it would actually be doing its job (being oxidized instead of some other molecule), so perhaps this is not an issue.
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Bottled water may have been treated with ozone - residue that would oxidize your copper. Industrial ozonated systens use UV to eliminate the stuff. Activated carboon works - you might try bisulfite addition to test the concept.
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actually bisulfite would just address oxidation. You know that’s happening but a little might let you proceed
There are kits for ozone but I don;t know if they just look for general oxidation potential. https://www.hannainst.com/hi38054-ozone-test-kit.html?msclkid=7d6f1025ce521934fd02748b5ee1471a
hannainst.com
The HI38054 is a chemical test kit for the determination of ozone.
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UPDATE:
It appeared the problem is water. Distilled water apparently is not the same as deionized water. Due to metal ions in water the copper part of Copper PCA was replaced with these free ions. Then copper ions oxidized. The solution was to replace the water source to have deionized water. The good source is water after reverse osmosis filter without remineralization step.
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