HPLC-MS Detection of Nonylphenol Ethoxylates and Lauryl Ethoxylates in Foodstuffs and the Inner Coatings of High-Barrier Pouches

The widespread use of non-ionic surfactants, e.g., nonylphenol ethoxylates or dodecyl ethoxylates, may result in their occurrence in foodstuffs. In this paper, extracts from the coatings and from the contents of high-barrier food pouches were analyzed by high-pressure liquid chromatography-mass spectrometry. These flexible pouches are an alternative package format of growing interest which can replace traditional cans. In almost all samples, nonylphenol ethoxylates and dodecyl ethoxylates were detected. The identified nonylphenol ethoxylates usually contained 4-10 oxyethylene units, while the identified dodecyl ethoxylates contained 3-13 oxyethylene units. However, in a few samples, longer fractions of dodecyl ethoxylates were detected, namely those containing >15 oxyethylene units. A comparison of the non-ionic surfactant concentrations in the coating extracts with their concentrations in the content extracts indicated that the coating materials were not the main sources of the contents' contamination. Other contaminants, namely BADGE conjugates and cyclic cooligoesters, which are common contaminants of canned foodstuffs, were found to rarely occur in high-barrier food pouches. Unexpectedly, in one sample polypropylene glycol was detected at a low concentration; this compound has not been previously identified as a potential food contaminant.