Surfactants

We routinely analyze for anionic and nonionic surfactants, particularly in industrial cleaners, using our Waters Alliance HPLC System with fluorescence or ELSD (evaporative light scattering) detection. Commonly encountered anionic surfactants include linear alkylsulfonates (LAS); common nonionic surfactants are alcohol ethoxylates (AE) and alkylphenol ethoxylates (POE). These surfactants can be measured at the high ppb level with fluorescence detection and into the ppm range with the ELSD.

The HPLC conditions:

• HPLC column: Spherisorb C1, 4.6 x 250 mm, 5 um with CN guard column
• Solvent: Acetonitrile/water (65:35)
• Flow rate: 1 ml/min
• Fluorescence detector: Excitation wavelength: 225nm; Emission wavelength: 290nm Samples should be filtered with 0.45um syringe filters before analysis.

Total nonionic surfactants can be measured by a two-phase titration method if HPLC is not available or not preferred.

For more information on our HPLC Group analytical capabilities contact Teresa Chow at 217-244-8912.