SDS quantitation and removal with resins

[Colthechemist]

Scott Coutts <scott.coutts at med.monash.edu.au> wrote in message news:<3F024A95.40702 at med.monash.edu.au>...
> Hi!
> 
> Does anyone know of a way that I can assay for SDS concentration in a
> sample containing protein? I want to know how much detergent remains 
> after attempts at removal. I need to assay for regular (non-labelled) 
> SDS, by the way.

ASTM D1681-92(1997) Standard Test Method for Synthetic Anionic Active
Ingredient in Detergents by Cationic Titration Procedure (see last
page)  http://www.techstreet.com/cgi-bin/detail?product_id=6966  will
give you total SDS. BDH sell the cationic titrant Hyamine 1622 0.004M
( which can be used instead of CTAB) and the dimidium
bromide-disulphine blue mixed indicator. The endpoint is very sharp
provided you are not color-blind!

> Also, I'm thinking of removing the SDS from some protein samples using a
> resin, perhaps Dowex 1-X2 or 1-X8 or similiar. I'm thinking of doing it
> in a batch method and then spinning the resin out through a frit. Does
> anybody have any comments about this? I.e. are there better resins for
> this type of application? Better ways of going about it? Is this likely
> to be more efficient than acetone or TCA precipitation (I don't care
> about protein function or recovery of secondary/tertiary structure).
> 
> Lastly, does anyone have any experience with Pierce's "SDS-Out" 
> precipitation reagent? Anybody know what's in it?

It could be a long chain quaternary ammonium compound such as the
cationic titrants mentioned above.

> Thanks!