Determination of Endocrine-Disrupting Nonylphenols and Nonylphenol Carboxylates by High-Performance Liquid Chromatography-Tandem Mass Spectrometry: Levels in German Food after Restriction

Abstract

Nonylphenols (NPs) and nonylphenol carboxylates (NPECs) are products of the biodegradation of nonylphenol ethoxylates (NPEOs), which is a widely used group of nonionic surfactants. These compounds are persistent, toxic, and exhibit estrogenic activity. Global scientific and public discourse has revealed the consequences of long-term dietary exposure to these endocrine disrupters. Since 2005, the utilization and sale of NPEOs and NPs have been regulated in some industrial applications by Directive 2003/53/EC of the European Union (EU). The objective of this investigation was to assess the NPs and NPECs concentration levels in foodstuffs following the implementation of the EU directive. Using a method based on high-performance liquid chromatography combined with tandem mass spectrometry (HPLC-MS), NPs and NPECs were determined in the same German food basket that was examined before the restriction. NPs were detected in 22 of the 24 food samples, whereas NPECs were below the limit of detection. The concentrations of NPs on a fresh weight basis varied between 0.1 and 6.3 μg kg⁻¹. Based on the data of food consumption rates in Germany and the concentrations of NPs in the food samples, the daily NP intake for an adult was determined to be 2.7 µg day⁻¹, which is one-third of the value found in the 2002 study. However, our findings revealed that NPs remain ubiquitous in foods at relevant concentrations, which highlights the need for further examinations in particular the isomer-specific aspects. This is especially important as nonylphenol is found in human blood in many studies.

Keywords:

• Directive 2003/53/EC
• endocrine-disruptors nonylphenols and nonylphenol carboxylates
• high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS)