NP/NPEs, also known as nonylphenols and nonylphenol ethoxylates, are nonionic surfactants, or detergent-like substances, with uses that lead to widespread release into aquatic environments. NPEs are used as detergents, emulsifiers, wetting agents, industrial processes, personal hygiene, automotive, latex paints, and lawn care products. Their presence in the environment is solely due to human activities, and mainly from WWTPs (waste water treatment plant) and direct discharge. Over 80% of alkylphenol produced are nonylphenol based compounds. The rest are mostly octylphenol based compounds.
NPEs are degraded to shorter chain nonylphenol ethoxylates as well as shorter nonylphenol ethoxycarboxylates under aerobic condition, before being biodegraded to nonylphenol. Shorter ethoxylate chain NPEs have greater toxicity than longer ones. These shorter chain NPEs have been reported to cause a number of estrogenic responses on aquatic organisms and thus they have been classified as endocrine disruptors (EDCs) by several organizations2. We have developed a method using liquid chromatography coupled with mass spectrometry for identification and quantitation of NPEs.