Advances in detection methods, environmental distribution and toxic effects of p-phenylenediamine antioxidants

N,N′-Substituted p-phenylenediamines (PPDs) are synthetic antioxidants used in rubber, with their environmental presence and risks being a concern. They transform into toxic quinone derivatives (PPD-Qs) in the environment, affecting ecosystems and posing health risks. Current research on their environmental levels, transformation, and toxicity is limited. This review covers detection methods, environmental presence, transformation mechanisms, and toxicity of PPDs and PPD-Qs to inform risk assessment and control. Common extraction methods include ultrasonic and solid-phase extraction, with LC-MS/MS being an effective detection technique. PPDs and PPD-Qs enter the environment through tire wear, industrial emissions, and sewage treatment. They are found in various environmental media, showing complex behaviours. They also have potential toxic effects on aquatic life, mammals, and humans, with N-(1,3-dimethylbutyl)-N′-phenyl-1,4-phenylenediamine quinone being highly toxic to aquatic organisms. Future work should optimize extraction and detection methods and study their environmental impacts for ecological risk management.