sodium dodecyl sulfate in mobile phase

Discussions about HPLC, CE, TLC, SFC, and other "liquid phase" separation techniques.

7 posts Page 1 of 1
Is it common to see foaming in mobile phase when using sodium dodecyl sulfate in the preparation?
Especially if that mobile phase is still 100% aqueous !!! Sodium dodecyl sulfate is a great anionic surfactant !
Consumer Products Guy wrote:
Especially if that mobile phase is still 100% aqueous !!! Sodium dodecyl sulfate is a great anionic surfactant !


Would you suggest the SDS solution needs to settle for long before adjusting the pH?
Mouleyre wrote:
Would you suggest the SDS solution needs to settle for long before adjusting the pH?

There is a method for tranexamic acid related substances in Eur. Ph. with the following MP preparation:

Dissolve 11.0 g of anhydrous sodium dihydrogen phosphate R in 500 mL of water R and add 5 mL of triethylamine R and 1.4 g of sodium laurilsulfate R. Adjust to pH 2.5 with dilute phosphoric acid R and dilute to 600 mL with water R. Add 400 mL of methanol R and mix.

SDS makes the buffer solution foaming, but this is not critical. No precautions are needed to adjust the pH of this solution.
I have visions of someone trying this on a ELSD or CAD. Of course it would kill the detector because it's non-volatile, but just imagine what the lab would look like after half an hour or so...
And once the methanol is added, suds should be a non-issue.

I might determine accurately how much phosphoric acid I needed to add, then after that first time add the phosphoric acid by weight or volume for subsequent batches.
With our mixed-mode columns you have ion-pairing reagent attached to the surface. Nothing is going to ever foam :).
Contact me if you would like to chat about any of your applications which uses ion-pairing reagents and how to convert them to methods fully compatible with MS, ELSD, CAD or UV.
Vlad Orlovsky
HELIX Chromatography
My opinions might be bias, but I have about 1000 examples to support them. Check our website for new science and applications
www.helixchrom.com
7 posts Page 1 of 1

Who is online

In total there is 1 user online :: 0 registered, 0 hidden and 1 guest (based on users active over the past 5 minutes)
Most users ever online was 1117 on Mon Jan 31, 2022 2:50 pm

Users browsing this forum: No registered users and 1 guest

Latest Blog Posts from Separation Science

Separation Science offers free learning from the experts covering methods, applications, webinars, eSeminars, videos, tutorials for users of liquid chromatography, gas chromatography, mass spectrometry, sample preparation and related analytical techniques.

Subscribe to our eNewsletter with daily, weekly or monthly updates: Food & Beverage, Environmental, (Bio)Pharmaceutical, Bioclinical, Liquid Chromatography, Gas Chromatography and Mass Spectrometry.

Liquid Chromatography

Gas Chromatography

Mass Spectrometry