Advances in Analytical Determination Methods and Toxicity and Health Risk Assessment of 6PPD and Its Transformation Products in Food

<i>N</i>-(1,3-Dimethylbutyl)-<i>N</i>'-phenyl-<i>p</i>-phenylenediamine (6PPD) is a member of the <i>p</i>-phenylenediamines (PPDs), recognized as a highly effective antioxidant. It has been extensively employed in the automotive tire manufacturing industry, and plays a critical role in enhancing the durability and service life of rubber materials. In recent years, significant research has demonstrated that 6PPD-quinone (6PPD-Q), the transformation product of 6PPD, is a toxic substance that causes the acute death of coho salmon (<i>Oncorhynchus kisutch</i>). The toxicity of its aquatic organisms has attracted great attention of scholars, and 6PPD-Q has been regarded as the emerging contaminant. It has been reported that 6PPD diffuses from rubber debris into environmental media such as air, soil, and water after the tires wear. 6PPD and 6PPD-Q have been widespread in the environment, and they migrate into food through the environment and enter the human body through exposure routes such as dietary intake and drinking water, posing potential risks to human health. This paper reviewed the current reports on the toxicity and health risks of 6PPD and 6PPD-Q, and compares the advantages and disadvantages of sample pretreatment methods and detection technologies of 6PPD and 6PPD-Q in different food matrices, and provides a scientific basis for food safety risk assessment. Evidence indicated that 6PPD-Q exhibits not only acute aquatic toxicity but also cytotoxicity, hepatotoxicity, neurotoxicity, and genotoxicity. Epidemiological data suggest a significant association between elevated 6PPD-Q levels and increased risks of colorectal cancer and liver abnormalities. There remains an urgent need to develop comprehensive, standardized, and high-throughput analytical methodologies for the efficient screening of 6PPD and 6PPD-Q in food samples, along with expanded dietary exposure assessments, to fully characterize the impacts of 6PPD and 6PPD-Q on human health.