Commercial nonylphenol polyethoxylates, designated as NPnEOs, where n is the number of ethoxy groups, are commonly used as non-ionic surfactants in households, industry and agriculture worldwide.According to the starting material nonylphenol, they may also be composed of a complex mix of isomeric nonyl substituents.In order to study more fully the heterogeneity arising from both the ethoxylate and nonyl groups, a mixture of NPnEOs was first fractionated by normal phase liquid chromatography (NPLC) into separate fractions.These fractions comprise individual ethoxymers-ie.single n ethoxy moiety.However there is no differentiation of the isomeric alkyl group.