Molecular weight and EON distribution of industrial polyethoxylated surfactants by high performance size exclusion chromatography

Polyethoxylated nonionic surfactants were analyzed by high performance size exclusion chromatography (HPSEC) using different pore size Ultrastyragel columns with tetrahydrofuran (THF) as mobile phase. Not only does HPSEC provide molecular weight distribution but also ethylene oxide number (EON) average estimation over a wider EON range. In this work, the analysis is extended to others nonionic ethoxylated surfactants and the application of this procedure for manufacturers and formulators is discussed. Calibration plots using polystyrenes standard and three polyethoxylated surfactants groups exhibit an excellent linearity and parallelism with the same slope indicating that calibration with the Q-factor approach can be used to calculate molecular weight and EON average in this type of samples.