Hello, everyone,

After a year of attempts to develop an HPLC method for Germall (cosmetic preservative)we would like to try colorimetry. I saw it mentioned in archives. Is there anyone willing to share colorimetry method for Germall 2 or Germall 115?
My product is a cream.

Thank you

Why did you abandon HPLC as approach? Do you have problem with stability or retention time? Are separating Germall 2 from Germal 115? Would you provide more details?

Stability in solution is a problem. Seems to exist as a mixture of different entities that undergo continuous changes. We do not need to separate Germall 2 from Germall 115, they are in different products, but the problem is same.

Ask supplier, they're supposed to be "the experts" on their own products. Unfortunately, this is oftentimes not the case, but worth trying them first anyway. My company does not use these preservatives, so I have no hands-on experience.

Did that, can't use the Raw material method. Many nitrogen sources in the sample. Are there anybody out there who analyses these preservatives? They have been used since the 1960-s, I think.

I know that this is not a lot of help, but I seem to remember looking into this a few years ago. One of the suppliers gave me a reference for the analysis that appeared in a chromatography journal. You may want to do a lit search that would go back about 5 or 6 years. I am no longer with the company that I was at when I got the info, so do not have it at hand. Sorry that I can't be of more help.

I can't find the optimal conditions to analyse Germall 115 by HPLC in reversed phase. I use a LiChrospher C18 column (Merck) and acetonitrile/water with acetic acid as mobile phase. Can you help me please ? thank you.