Chromatography Forum

I am trying to develop a "robust" method for detecting detergent/surfactant adulteration in an array of raw materials. On two occassions in the past 5 years, two raw materials were adulterated with detergent/surfactant after the manufacturer switched cleaning methods in one and did not inform us, and another where the raw material was synthesized in the same vessel as another but not cleaned thoroughly between synthesis. The first instance was not detected until it reach our customers and protocols were put in place to try to prevent that from happening again. The second incident was detected during routine QC testing and the lots rejected utilizing the cell based assays developed after the initial incident.

As a result of these instances, I was thinking about trying to develop a GC/MS or LC/MS method for detecting detergent/surfactant adulteration of raw materials so that if an investigation occurs again, we could quickly try to screen the raw material and see if a detergent/surfactant was responsible.

I chose a mixture of non-ionic, anionic and cationic detergents to test but have not had any luck derivatizing and detecting by BSTFA using GC/MS. Anyone have any ideas? I have looked through the literature but unfortunately nothing specific enough to be useful (outside a couple papers) or generic to screen a multitude of detergent types. Eventually, I will have to do SPE on the raw materials but right now, I am just focusing on a sensitive method that will detect an array of different types of detergents based on making standard solutions. Any help or guidance would be appreciated. Thanks!

Here are a few detergents I was looking at:

N,N-Dimethyldodecylamine N-oxide



Sodium dodecyl sulfate



Hexadecyltrimethylammonium bromide



Docusate sodium salt

Have you tried colorimetric analysis, like with methylene blue or dimidium bromide -disulfine blue? They're pretty sensitive.

Have you tried colorimetric analysis, like with methylene blue or dimidium bromide -disulfine blue? They're pretty sensitive.

I am not even aware of it...I will look into it. Thank you!