I need to analyze the sodium lauryl sulfate content in laundry detergent product which contain 2 anionic surfactants (10-30% sodium alkylbenzene sulfonate (LAS) and 0-5% sodium lauryl sulfate (SLS)). I usually do following procedure:
I think this process is very time consuming and labor-intensive.
That's why, I've been trying to switch to automatic potentiometric titrator. This could produce good result for total LAS+SLS. However, I couldn't get good titration curve (fluctuative, no equivalence point) for sample after acid hydrolysis.
Does anybody could suggest what's wrong or is there any other method that is simpler and reliable to directly check SLS content?
Thank you in advance.
Agnes Veronica Victoria
We have developed a method for separate thermometric titration of sodium alkyl sulfates and sodium alkylbenzene sulfonates with cationic hydrotrope with s-benzyl isothiuronium chloride. It forms insoluble salts with anionic surfactants. Aromatics are more stable. Try potentiometric titration. Titrate in acidic or neutral media. In an alkaline environment, BITX decomposes with the formation of mercaptan. If you try, seek advice.
Please, you can find some alternative methods in this review: Article Methods for the determination of anionic surfactants
Thank you Yuri Mirgorod and Jp Wu for the recommendation.
Mikhail Y. Pletnev I have read the article earlier but I appreciate your reference. Now, I am trying to analyze SLS using HPLC RID but still trying to find the suitable sample preparation method.
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