Chromatography Forum

I need to analyze empty capsule shells for SLS content (sodium lauryl sulfate)qualitatively or quantitatively. Please suggest your ideas/methods.

Thanks

ASTM 3049-89 (reapproved 2003) mixed indicator titration.

Could you please give more information about this method. I appreciate if you can give specific details like how to perform etc.

Thanks

It's in the ASTM, look it up, I'd guess it's copyrighted material.

could you please provide further information? Are there any titration methods available?

Thanks in advance

Could any of the experts proivde links to the analysis of sodium lauryl sulfate content by LC or by any method?

I appreciate your help

Here is application for alkylsulfonic acids, you will need more ACN in the mobile phase for your compound:
http://www.sielc.com/application_144.html

Thank you very much for the information Vlad Orlovsky. Do you think that ammonium acetate 10mM with acetonitrile gradient from 5% of acetonitrile to 50% would give you some hopeful data? I would definetely try this with primesep and are there any other methods by UV instead of ELSD for quantitating SLS content? I would guess the sulfates can not detect by UV?

Thanks for your help.

ELSD detection is widely used for detecting excipients such as Tween 80,
PEG's and other non-chromophore containing entities.

I doubt if the lauryl sulfate has a chromophore in it, hence the ELSD application. But, that is only my thought.

It's in the ASTM, look it up, I'd guess it's copyrighted material.

could you please provide further information? Are there any titration methods available?

ASTM 3049-89 (reapproved 2003) is a mixed indicator titration procedure. Am I correct that in the four months from August until your recent post that you did not try that? As the Soup Nazi said on the Seinfeld show: "No more for you" !!!

You don't need to start with 5% ACN, you can go from 25 to 60% for example and 10 mmol of ammonium acetate.
SLS has no UV activity, so you need ELSD, CAD, RI or MS

May i know what is ASTM 3049-89? I would really appreciate if you could give me some specifics.

ASTM is American Society for Testing and Materials; this material is copyrighted, one needs to purchase. If you had gone this route, you might have completed this last August.

http://engineers.ihs.com/document/abstr ... AAAAAAAAAA

Thanks for all the information. I will definetely try the ASTM route and Primecep with ELSD. What primesep column would be a good start? Is it should be a primesep 500? or any primesep that i could use? I have some primesep columns but i need to check what kind they are. Please let me know thanks a lot for all of your help.

How much SLS do your samples contain? Or what is the detection limit requirement? If the SLS concentration is too low, say below 10 ppm, then ELSD may not be sensitive enough to provide reliable quantitation.