zno and ph in a lotion
Good night, i am working on a lotion using 8percent or more zno. this zno is not coated with silica dimethicone or anything else. As i know the ph should be 7 or lower(5 or 6). I have used citric acid and metered the ph of lotion 5,7. 1 or 2 hours later i metered the ph of lotion 7,1. why it has increased. what should i do saving my zno becoming an anion. Please help me. I am accepting book suggestions of this topic too. Thank you a lot.