The substituted p-phenylenediamines (PPDs) represent a family of effective antioxidants broadly applied in rubber industries. Recently, our group identified 6PPD-quinone, an ozonation product of the tire antioxidant 6PPD, to be highly toxic to coho salmon. Human may also be exposed to 6PPD-quinone and the PPD antioxidants through rubber consumer products, but such risk has not been characterized. Here, we investigated the occurrences of 6PPD-quinone and six major PPD antioxidants in thirteen kinds of rubber products. 6PPD-quinone was quantitatively analyzed with LC-MS/MS, and was detected in various rubber products such as crumb rubber (13 ± 11 µg/g), doormat (16 ± 6 µg/g), and rubber stopper (1.6 ± 0.2 µg/g). PPD antioxidants were identified with LC-qTOF-HRMS through suspect screening, and multiple PPDs antioxidants were detected, including 6PPD, DPPD, DTPD, and DNP. Our results highlighted the human exposure risks of 6PPD-quinone and PPD antioxidants and will attract future attention to this hazard.

Occurrence of substituted p-phenylenediamine antioxidants in consumer products

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.