chemistry eye treatments

[tara1]

Hi

Hope someone can help with part of an assignment i'm doing on eye treatments.
i need to know the basic chemistry affecting the shelf life of tints and hydrogen peroxide. if anyone can help or direct me in the right way i'd be eternally gratefull

 

[Ruth Mills]

Here's the Wikipedia entry for the decomposition of hydrogen peroxide... Hydrogen peroxide - Wikipedia, the free encyclopedia

I guess the bottom line here is that hydrogen peroxide is unstable and will spontaneously decompose over time.

Do you have any info as to the dye ingredients in the eyelash tints that you are using?

 

[LookGood]

I have this in my assignment at college and cannot find the information anywhere. Hope you can help???

Using Hydrogen Peroxide with Tint ingredients... Water, Cetearyl Alcohol, Sodium Cetearyl Sulfate, Sodium Laureth Sulfate, p-Phenylenediamine

 

[Ruth Mills]

I have this in my assignment at college and cannot find the information anywhere. Hope you can help???

Using Hydrogen Peroxide with Tint ingredients... Water, Cetearyl Alcohol, Sodium Cetearyl Sulfate, Sodium Laureth Sulfate, p-Phenylenediamine

Ah, now I see... well out of the tint ingredients there, it would be the p-Phenylenediamine that would be responsible for the actual tinting; it's a black dye derived from coal tar and quite a heavy duty one at that; I'd be pretty sure that the concentration of it would be significantly less than in a black hair dye as it can be pretty nasty stuff!

The Cetearyl Alcohol would act as an emollient and emulsifier; and the sodium cetearyl sulfate and sodium laureth sulfate are surfactants; these would be present to "bulk" the tint out and stop the constituents from separating out.

The Hydrogen Peroxide is an oxidizing agent which is required for the dye to react and helps open up the hair shaft to allow the dye to be absorbed.

 

[Ruth Mills]

I have this in my assignment at college and cannot find the information anywhere. Hope you can help???

Using Hydrogen Peroxide with Tint ingredients... Water, Cetearyl Alcohol, Sodium Cetearyl Sulfate, Sodium Laureth Sulfate, p-Phenylenediamine

Actually, reading the question again concerning the *shelf life* rather than the method of action on the eyelashes, I would say that the peroxide is the critical factor here; as in my previous comment with the Wikipedia link to hydrogen peroxide, it's an unstable substance and spontaneously degrades into water and oxygen over time. Whereas the ingredients of the tint itself (water, cetearyl alcohol, sodium cetearyl sulfate, sodium laureth sulphate, p-phenylenediamine) are all relatively stable and should not degrade significantly over time - certainly not at the same rate as the peroxide anyway!