Quaternary Ammonium Surfactant Testing

Quaternary Ammonium surfactants, or "Quats" for short are widely used in household products from detergents to anti-static dryer sheets and fabric softeners. They work as surfactants because they possess a fixed positive charge at one end and long water insoluble carbon chains (usually one or two) at the other.

To detect and quantify Quats, ISI uses a High Pressure Liquid Chromatograph (HPLC) equipped with a conductivity detector. This type of detector responds to the positive charge and, combined with the separating power of the HPLC, is very specific for Quats. Our fully validated method is able to recover the Quats from water or wastewater and determine the amounts present with a detection limit as low as 0.1 ppm. The technique is ideally suited for determining the residual Quat concentration in Biodegradation trials such as OECD method 301. As a useful back-up to the HPLC test, we also routinely perform a colour test which responds specifically to quaternary ammonium compounds.