HydroCarbon - 23-9-2010 at 20:18
Hello, I want to know if this is likely to work.
I want to determine if a lab detergent contains stearate or not. The detergent is Fisherbrand Sparkleen 1 MSDS . The MSDS shows some of the ingredients, but it doesn't show them all it leaves off about 40% of the contents as "non-hazardous
ingredients" I believe this is where the stearate is hiding as either the potassium or sodium salt.
My plan is to make a concentrated solution of Sparkleen in DI water, then add a concentrated solution of calcium chloride. I'm hoping this will
precipitate out the stearate as calcium stearate, which I can then confirm by IR spec.
Will this work? And is it possible that the calcium chloride will cause some of the other ingredients to precipitate out (Sodium
dodecylbenzenesulfonate, and/or sodium carbonate)?
ScienceSquirrel - 24-9-2010 at 02:37
The sodium carbonate is going to precipitate out loads of calcium carbonate when you add the calcium chloride solution.
I doubt your detergent contains any stearate at all. I think the two detergents contained in it are Ethylene oxide-nonylphenol polymer and Sodium
dodecylbenzenesulfonate.
Stearic acid is only poorly soluble in water and the presence of a strong acid makes it even more insoluble. Try adding dilute sulphuric acid to a
strong soap solution and you will obtain an immediate waxy precipitate.