The migration and degradation of N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine from rubber hoses in milk lines

Abstract

N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD), an anti-ageing agent in rubber hoses used in milk lines, may migrate into the milk and cause safety issues. Thus its migration and degradation in simulants/milk were studied to explore the changing trends and final levels, by high-performance liquid chromatography. The results showed that 6PPD continuously increased in 95% ethanol and degraded more easily in simulants with a high water content. The degradation may be attributed to the π-conjugated system of 6PPD and smaller steric hindrance of degradation products. No migration was observed into milk after 10 min. This study provides a novel and effective approach to evaluating 6PPD trends and safety for the dairy industry.