Nonylphenol polyoxyethylene ether (NPEO) is an anhydrous mixture formed by the condensation of nonylphenol and ethylene oxide, and belongs to non-ionic surfactants. NPEO has a wide range of applications in the fields of detergents, printing and dyeing, and chemical engineering. It has certain abilities to penetrate, emulsify, disperse, resist acid and alkali, and resist reduction and oxidation. However, at the same time, NPEO has high biodegradability and may have toxic effects on aquatic organisms in the environment.

NPEO is a homogenous mixture composed of different polymerization degrees and different nonyl structures. Currently, the detection methods for NPEO and its degradation products mainly include gas chromatography-mass spectrometry (GC-MS) and liquid chromatography (HPLC). Among them, HPLC detection method is relatively simple, with low reagent toxicity and the ability to simultaneously separate different EO numbers. Therefore, in this experiment, the liquid chromatography tandem evaporative light scattering detector method was used, and a special chromatographic column separation mode was configured to achieve NPEO detection with different EO numbers.