Re: nonionic detergents

Steve Latshaw (latshaws@mis.finchcms.edu)
Mon, 4 May 1998 10:09:42 -0500

I can't give you any references because the methods I used were all
from working in an industrial manufacturing setting and also what I would
now consider trace analysis are irrelevant to the manufacture of surfactants.
We only used GC to confirm the average MW of the surfactant in
question or its starting material, which for non-PE based surfactants was
coconut oil, but quantitation was adding the area under all the peaks in
question (TC detection) and looking for the proper ratios.
Another method was gravimetric, where the oil could be extracted
with organic solvent then passed thru sodium sulfate to completely remove
any water and dry the solvent in a weigh-boat.
The simplest test we did was HPLC-based where we packed our own
columns with a mixed bed ion-exchanger and used a 70% methanol-water mobile
phase with RI detection and quantitation against some standards.

Good Luck,
Steve Latshaw
Chicago Medical School

At 03:45 PM 5/1/98 -0400, VERNON SHOUP wrote:
>Several days ago, I submitted a note asking for analysis methods for
nonionic detergents, and the response was deafeningly quiet. In the
meantime, I came up with a gas chromatography method:
>
> "Analysis of Triton X-100 (Nonionic Detergent) Using the HP 5890
> Series II Gas Chromatograph" by P. Sandra, F. David and Roger L.
> Firor, August 1989
> HP Application Note 228-103
>
>In this method, the Triton X-100 is silylated with BSTFA. A capillary
column is used with hydrogen carrier gas, and a temperature gradient from
80C to 400C is applied. A large number of peaks (>16) are observed because
of the expected heterogeneity (MWs from 250 to 1100).
>So here are my questions:
>
> 1. Is GC the method of choice for analysis of nonionic detergents?
> 2. Are there any HPLC methods that might be used? I assume the extreme
heterogeneity (from a biochemist's viewpoint) makes rpHPLC not a viable option.
>
> 3. If I inject an aqueous samples (containing Triton X-100) onto a
rpHPLC column, do these detergents interfere with other analyses? i.e. do
the various species come off all over the place, or do they stick and change
the chromatographic characteristics of the column?
>
>Vernon
>
>Vernon A. Shoup
>QC, Regeneron Pharmaceuticals
>Rensselaer, NY 12144
>
>(518)488-6012
>vernon.shoup@regpha.com
>
>